diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 44f8f6f..9e86d96 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -11,7 +11,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9]
+        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11']
         os: [macos-latest, windows-latest, ubuntu-latest]
     steps:
     - uses: actions/checkout@v1
@@ -80,7 +80,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9]
+        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11']
         # ubuntu wheel is built in `manylinux_build.yml`
         os: [macos-latest, windows-latest]
 
diff --git a/.github/workflows/manylinux_build.yml b/.github/workflows/manylinux_build.yml
index 7fbc8c1..b67e1f8 100644
--- a/.github/workflows/manylinux_build.yml
+++ b/.github/workflows/manylinux_build.yml
@@ -9,15 +9,11 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: 
-          - 3.6
-          - 3.7
-          - 3.8
-          - 3.9
+        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11']
     container: 
-      image: quay.io/pypa/manylinux2010_x86_64
+      image: quay.io/pypa/manylinux2014_x86_64
       env:
-        PATH: /root/.cargo/bin:/root/.local/bin:/opt/python/cp36-cp36m/bin:/opt/python/cp37-cp37m/bin:/opt/python/cp38-cp38/bin:/opt/rh/devtoolset-2/root/usr/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/opt/python/cp35-cp35m/bin:/opt/python/cp36-cp36m/bin:/opt/python/cp37-cp37m/bin:/opt/python/cp38-cp38/bin:/opt/python/cp39-cp39/bin:/opt/rh/devtoolset-8/root/usr/bin
+        PATH: /root/.cargo/bin:/root/.local/bin:/opt/python/cp36-cp36m/bin:/opt/python/cp37-cp37m/bin:/opt/python/cp38-cp38/bin:/opt/rh/devtoolset-2/root/usr/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/opt/python/cp35-cp35m/bin:/opt/python/cp36-cp36m/bin:/opt/python/cp37-cp37m/bin:/opt/python/cp38-cp38/bin:/opt/python/cp39-cp39/bin:/opt/python/cp310-cp310/bin:/opt/python/cp310-cp310/bin:/opt/rh/devtoolset-8/root/usr/bin:/opt/_internal/cpython-3.11.1/bin:/opt/_internal/cpython-3.10.1/bin
       options: --user root
     env:
       HOME: /root
@@ -27,6 +23,8 @@ jobs:
     - name: Install rust
       run: |
         curl --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --profile minimal
+    - name: install gcc
+      run: yum -y install gcc
     - name: Test rust lib
       run: cargo test
 
diff --git a/python/.gitignore b/python/.gitignore
index 99ac6b2..115b1f6 100644
--- a/python/.gitignore
+++ b/python/.gitignore
@@ -153,4 +153,4 @@ Cargo.lock
 # These are backup files generated by rustfmt
 **/*.rs.bk
 
-
+/.venv37
diff --git a/python/Cargo.toml b/python/Cargo.toml
index b92000e..aaf7d38 100644
--- a/python/Cargo.toml
+++ b/python/Cargo.toml
@@ -7,12 +7,12 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-textspan = "0.5.2"
+textspanrs = { package = "textspan", version = "0.5.2"}
 
 [lib]
 name = "textspan"
 crate-type = ["cdylib"]
 
 [dependencies.pyo3]
-version = "^0.13"
+version = "0.17.3"
 features = ["extension-module"]
diff --git a/python/poetry.lock b/python/poetry.lock
index e913c4e..b46452f 100644
--- a/python/poetry.lock
+++ b/python/poetry.lock
@@ -1,207 +1,204 @@
-[[package]]
-category = "dev"
-description = "Asyncio support for PEP-567 contextvars backport."
-marker = "python_version < \"3.7\""
-name = "aiocontextvars"
-optional = false
-python-versions = ">=3.5"
-version = "0.2.2"
-
-[package.dependencies]
-[package.dependencies.contextvars]
-python = "<3.7"
-version = "2.4"
+# This file is automatically @generated by Poetry and should not be changed by hand.
 
 [[package]]
-category = "dev"
-description = "Atomic file writes."
-marker = "sys_platform == \"win32\""
-name = "atomicwrites"
-optional = false
-python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
-version = "1.4.0"
-
-[[package]]
-category = "dev"
-description = "Classes Without Boilerplate"
 name = "attrs"
+version = "22.2.0"
+description = "Classes Without Boilerplate"
+category = "dev"
 optional = false
-python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
-version = "19.3.0"
+python-versions = ">=3.6"
+files = [
+    {file = "attrs-22.2.0-py3-none-any.whl", hash = "sha256:29e95c7f6778868dbd49170f98f8818f78f3dc5e0e37c0b1f474e3561b240836"},
+    {file = "attrs-22.2.0.tar.gz", hash = "sha256:c9227bfc2f01993c03f68db37d1d15c9690188323c067c641f1a35ca58185f99"},
+]
 
 [package.extras]
-azure-pipelines = ["coverage", "hypothesis", "pympler", "pytest (>=4.3.0)", "six", "zope.interface", "pytest-azurepipelines"]
-dev = ["coverage", "hypothesis", "pympler", "pytest (>=4.3.0)", "six", "zope.interface", "sphinx", "pre-commit"]
-docs = ["sphinx", "zope.interface"]
-tests = ["coverage", "hypothesis", "pympler", "pytest (>=4.3.0)", "six", "zope.interface"]
+cov = ["attrs[tests]", "coverage-enable-subprocess", "coverage[toml] (>=5.3)"]
+dev = ["attrs[docs,tests]"]
+docs = ["furo", "myst-parser", "sphinx", "sphinx-notfound-page", "sphinxcontrib-towncrier", "towncrier", "zope.interface"]
+tests = ["attrs[tests-no-zope]", "zope.interface"]
+tests-no-zope = ["cloudpickle", "cloudpickle", "hypothesis", "hypothesis", "mypy (>=0.971,<0.990)", "mypy (>=0.971,<0.990)", "pympler", "pympler", "pytest (>=4.3.0)", "pytest (>=4.3.0)", "pytest-mypy-plugins", "pytest-mypy-plugins", "pytest-xdist[psutil]", "pytest-xdist[psutil]"]
 
 [[package]]
-category = "dev"
-description = "Cross-platform colored terminal text."
-marker = "sys_platform == \"win32\""
 name = "colorama"
+version = "0.4.6"
+description = "Cross-platform colored terminal text."
+category = "dev"
 optional = false
-python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
-version = "0.4.3"
+python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,!=3.5.*,!=3.6.*,>=2.7"
+files = [
+    {file = "colorama-0.4.6-py2.py3-none-any.whl", hash = "sha256:4f1d9991f5acc0ca119f9d443620b77f9d6b33703e51011c16baf57afb285fc6"},
+    {file = "colorama-0.4.6.tar.gz", hash = "sha256:08695f5cb7ed6e0531a20572697297273c47b8cae5a63ffc6d6ed5c201be6e44"},
+]
 
 [[package]]
+name = "docstring-parser"
+version = "0.7.3"
+description = ""
 category = "dev"
-description = "PEP 567 Backport"
-marker = "python_version < \"3.7\""
-name = "contextvars"
 optional = false
-python-versions = "*"
-version = "2.4"
-
-[package.dependencies]
-immutables = ">=0.9"
+python-versions = "~=3.5"
+files = [
+    {file = "docstring_parser-0.7.3.tar.gz", hash = "sha256:cde5fbf8b846433dfbde1e0f96b7f909336a634d5df34a38cb75050c7346734a"},
+]
 
 [[package]]
+name = "exceptiongroup"
+version = "1.1.0"
+description = "Backport of PEP 654 (exception groups)"
 category = "dev"
-description = ""
-name = "docstring-parser"
 optional = false
-python-versions = "~=3.6"
-version = "0.7.2"
+python-versions = ">=3.7"
+files = [
+    {file = "exceptiongroup-1.1.0-py3-none-any.whl", hash = "sha256:327cbda3da756e2de031a3107b81ab7b3770a602c4d16ca618298c526f4bec1e"},
+    {file = "exceptiongroup-1.1.0.tar.gz", hash = "sha256:bcb67d800a4497e1b404c2dd44fca47d3b7a5e5433dbab67f96c1a685cdfdf23"},
+]
+
+[package.extras]
+test = ["pytest (>=6)"]
 
 [[package]]
-category = "dev"
-description = "A library for automatically generating command line interfaces."
 name = "fire"
+version = "0.3.1"
+description = "A library for automatically generating command line interfaces."
+category = "dev"
 optional = false
 python-versions = "*"
-version = "0.3.1"
+files = [
+    {file = "fire-0.3.1.tar.gz", hash = "sha256:9736a16227c3d469e5d2d296bce5b4d8fa8d7851e953bda327a455fc2994307f"},
+]
 
 [package.dependencies]
 six = "*"
 termcolor = "*"
 
 [[package]]
-category = "dev"
-description = "A library for property-based testing"
 name = "hypothesis"
+version = "6.61.0"
+description = "A library for property-based testing"
+category = "dev"
 optional = false
-python-versions = ">=3.5.2"
-version = "5.23.11"
+python-versions = ">=3.7"
+files = [
+    {file = "hypothesis-6.61.0-py3-none-any.whl", hash = "sha256:7bb22d22e35db99d5724bbf5bdc686b46add94a0f228bf1be249c47ec46b9c7f"},
+    {file = "hypothesis-6.61.0.tar.gz", hash = "sha256:fbf7da30aea839d88898f74bcc027f0f997060498a8a7605880688c8a2166215"},
+]
 
 [package.dependencies]
 attrs = ">=19.2.0"
+exceptiongroup = {version = ">=1.0.0", markers = "python_version < \"3.11\""}
 sortedcontainers = ">=2.1.0,<3.0.0"
 
 [package.extras]
-all = ["django (>=2.2)", "dpcontracts (>=0.4)", "lark-parser (>=0.6.5)", "numpy (>=1.9.0)", "pandas (>=0.19)", "pytest (>=4.3)", "python-dateutil (>=1.4)", "pytz (>=2014.1)"]
+all = ["backports.zoneinfo (>=0.2.1)", "black (>=19.10b0)", "click (>=7.0)", "django (>=3.2)", "dpcontracts (>=0.4)", "importlib-metadata (>=3.6)", "lark (>=0.10.1)", "libcst (>=0.3.16)", "numpy (>=1.9.0)", "pandas (>=1.0)", "pytest (>=4.6)", "python-dateutil (>=1.4)", "pytz (>=2014.1)", "redis (>=3.0.0)", "rich (>=9.0.0)", "tzdata (>=2022.7)"]
+cli = ["black (>=19.10b0)", "click (>=7.0)", "rich (>=9.0.0)"]
+codemods = ["libcst (>=0.3.16)"]
 dateutil = ["python-dateutil (>=1.4)"]
-django = ["pytz (>=2014.1)", "django (>=2.2)"]
+django = ["django (>=3.2)"]
 dpcontracts = ["dpcontracts (>=0.4)"]
-lark = ["lark-parser (>=0.6.5)"]
+ghostwriter = ["black (>=19.10b0)"]
+lark = ["lark (>=0.10.1)"]
 numpy = ["numpy (>=1.9.0)"]
-pandas = ["pandas (>=0.19)"]
-pytest = ["pytest (>=4.3)"]
+pandas = ["pandas (>=1.0)"]
+pytest = ["pytest (>=4.6)"]
 pytz = ["pytz (>=2014.1)"]
+redis = ["redis (>=3.0.0)"]
+zoneinfo = ["backports.zoneinfo (>=0.2.1)", "tzdata (>=2022.7)"]
 
 [[package]]
-category = "dev"
-description = "Immutable Collections"
-marker = "python_version < \"3.7\""
-name = "immutables"
-optional = false
-python-versions = ">=3.5"
-version = "0.14"
-
-[[package]]
-category = "dev"
-description = "Read metadata from Python packages"
-marker = "python_version < \"3.8\""
 name = "importlib-metadata"
+version = "6.0.0"
+description = "Read metadata from Python packages"
+category = "dev"
 optional = false
-python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,>=2.7"
-version = "1.7.0"
+python-versions = ">=3.7"
+files = [
+    {file = "importlib_metadata-6.0.0-py3-none-any.whl", hash = "sha256:7efb448ec9a5e313a57655d35aa54cd3e01b7e1fbcf72dce1bf06119420f5bad"},
+    {file = "importlib_metadata-6.0.0.tar.gz", hash = "sha256:e354bedeb60efa6affdcc8ae121b73544a7aa74156d047311948f6d711cd378d"},
+]
 
 [package.dependencies]
+typing-extensions = {version = ">=3.6.4", markers = "python_version < \"3.8\""}
 zipp = ">=0.5"
 
 [package.extras]
-docs = ["sphinx", "rst.linker"]
-testing = ["packaging", "pep517", "importlib-resources (>=1.3)"]
+docs = ["furo", "jaraco.packaging (>=9)", "jaraco.tidelift (>=1.4)", "rst.linker (>=1.9)", "sphinx (>=3.5)", "sphinx-lint"]
+perf = ["ipython"]
+testing = ["flake8 (<5)", "flufl.flake8", "importlib-resources (>=1.3)", "packaging", "pyfakefs", "pytest (>=6)", "pytest-black (>=0.3.7)", "pytest-checkdocs (>=2.4)", "pytest-cov", "pytest-enabler (>=1.3)", "pytest-flake8", "pytest-mypy (>=0.9.1)", "pytest-perf (>=0.9.2)"]
 
 [[package]]
-category = "dev"
-description = "iniconfig: brain-dead simple config-ini parsing"
 name = "iniconfig"
+version = "1.1.1"
+description = "iniconfig: brain-dead simple config-ini parsing"
+category = "dev"
 optional = false
 python-versions = "*"
-version = "1.0.1"
+files = [
+    {file = "iniconfig-1.1.1-py2.py3-none-any.whl", hash = "sha256:011e24c64b7f47f6ebd835bb12a743f2fbe9a26d4cecaa7f53bc4f35ee9da8b3"},
+    {file = "iniconfig-1.1.1.tar.gz", hash = "sha256:bc3af051d7d14b2ee5ef9969666def0cd1a000e121eaea580d4a313df4b37f32"},
+]
 
 [[package]]
-category = "dev"
-description = "Python logging made (stupidly) simple"
 name = "loguru"
+version = "0.5.3"
+description = "Python logging made (stupidly) simple"
+category = "dev"
 optional = false
 python-versions = ">=3.5"
-version = "0.5.1"
+files = [
+    {file = "loguru-0.5.3-py3-none-any.whl", hash = "sha256:f8087ac396b5ee5f67c963b495d615ebbceac2796379599820e324419d53667c"},
+    {file = "loguru-0.5.3.tar.gz", hash = "sha256:b28e72ac7a98be3d28ad28570299a393dfcd32e5e3f6a353dec94675767b6319"},
+]
 
 [package.dependencies]
-colorama = ">=0.3.4"
-win32-setctime = ">=1.0.0"
-
-[package.dependencies.aiocontextvars]
-python = "<3.7"
-version = ">=0.2.0"
+colorama = {version = ">=0.3.4", markers = "sys_platform == \"win32\""}
+win32-setctime = {version = ">=1.0.0", markers = "sys_platform == \"win32\""}
 
 [package.extras]
-dev = ["codecov (>=2.0.15)", "colorama (>=0.3.4)", "flake8 (>=3.7.7)", "isort (>=4.3.20)", "tox (>=3.9.0)", "tox-travis (>=0.12)", "pytest (>=4.6.2)", "pytest-cov (>=2.7.1)", "Sphinx (>=2.2.1)", "sphinx-autobuild (>=0.7.1)", "sphinx-rtd-theme (>=0.4.3)", "black (>=19.3b0)"]
-
-[[package]]
-category = "dev"
-description = "More routines for operating on iterables, beyond itertools"
-name = "more-itertools"
-optional = false
-python-versions = ">=3.5"
-version = "8.4.0"
+dev = ["Sphinx (>=2.2.1)", "black (>=19.10b0)", "codecov (>=2.0.15)", "colorama (>=0.3.4)", "flake8 (>=3.7.7)", "isort (>=5.1.1)", "pytest (>=4.6.2)", "pytest-cov (>=2.7.1)", "sphinx-autobuild (>=0.7.1)", "sphinx-rtd-theme (>=0.4.3)", "tox (>=3.9.0)", "tox-travis (>=0.12)"]
 
 [[package]]
-category = "dev"
-description = "Core utilities for Python packages"
 name = "packaging"
+version = "22.0"
+description = "Core utilities for Python packages"
+category = "dev"
 optional = false
-python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
-version = "20.4"
-
-[package.dependencies]
-pyparsing = ">=2.0.2"
-six = "*"
+python-versions = ">=3.7"
+files = [
+    {file = "packaging-22.0-py3-none-any.whl", hash = "sha256:957e2148ba0e1a3b282772e791ef1d8083648bc131c8ab0c1feba110ce1146c3"},
+    {file = "packaging-22.0.tar.gz", hash = "sha256:2198ec20bd4c017b8f9717e00f0c8714076fc2fd93816750ab48e2c41de2cfd3"},
+]
 
 [[package]]
-category = "dev"
-description = "plugin and hook calling mechanisms for python"
 name = "pluggy"
+version = "1.0.0"
+description = "plugin and hook calling mechanisms for python"
+category = "dev"
 optional = false
-python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
-version = "0.13.1"
+python-versions = ">=3.6"
+files = [
+    {file = "pluggy-1.0.0-py2.py3-none-any.whl", hash = "sha256:74134bbf457f031a36d68416e1509f34bd5ccc019f0bcc952c7b909d06b37bd3"},
+    {file = "pluggy-1.0.0.tar.gz", hash = "sha256:4224373bacce55f955a878bf9cfa763c1e360858e330072059e10bad68531159"},
+]
 
 [package.dependencies]
-[package.dependencies.importlib-metadata]
-python = "<3.8"
-version = ">=0.12"
+importlib-metadata = {version = ">=0.12", markers = "python_version < \"3.8\""}
 
 [package.extras]
 dev = ["pre-commit", "tox"]
+testing = ["pytest", "pytest-benchmark"]
 
 [[package]]
-category = "dev"
-description = "library with cross-python path, ini-parsing, io, code, log facilities"
-name = "py"
-optional = false
-python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
-version = "1.9.0"
-
-[[package]]
-category = "dev"
-description = ""
 name = "pydoc-md"
+version = "0.1.0"
+description = ""
+category = "dev"
 optional = false
 python-versions = ">=3.6,<4.0"
-version = "0.1.0"
+files = [
+    {file = "pydoc-md-0.1.0.tar.gz", hash = "sha256:5b64025c83d9230438bab6019ce570876a15a77e7f6bb83e0d1320ed34492700"},
+    {file = "pydoc_md-0.1.0-py3-none-any.whl", hash = "sha256:b2bcf3df7aa51d0bb40db9a67e5607caba64b7cdb1d791f40d2d7ef372449f85"},
+]
 
 [package.dependencies]
 docstring_parser = ">=0.7.2,<0.8.0"
@@ -209,205 +206,125 @@ fire = ">=0.3.1,<0.4.0"
 loguru = ">=0.5.1,<0.6.0"
 
 [[package]]
-category = "dev"
-description = "Python parsing module"
-name = "pyparsing"
-optional = false
-python-versions = ">=2.6, !=3.0.*, !=3.1.*, !=3.2.*"
-version = "2.4.7"
-
-[[package]]
-category = "dev"
-description = "pytest: simple powerful testing with Python"
 name = "pytest"
+version = "7.2.0"
+description = "pytest: simple powerful testing with Python"
+category = "dev"
 optional = false
-python-versions = ">=3.5"
-version = "6.0.1"
+python-versions = ">=3.7"
+files = [
+    {file = "pytest-7.2.0-py3-none-any.whl", hash = "sha256:892f933d339f068883b6fd5a459f03d85bfcb355e4981e146d2c7616c21fef71"},
+    {file = "pytest-7.2.0.tar.gz", hash = "sha256:c4014eb40e10f11f355ad4e3c2fb2c6c6d1919c73f3b5a433de4708202cade59"},
+]
 
 [package.dependencies]
-atomicwrites = ">=1.0"
-attrs = ">=17.4.0"
-colorama = "*"
+attrs = ">=19.2.0"
+colorama = {version = "*", markers = "sys_platform == \"win32\""}
+exceptiongroup = {version = ">=1.0.0rc8", markers = "python_version < \"3.11\""}
+importlib-metadata = {version = ">=0.12", markers = "python_version < \"3.8\""}
 iniconfig = "*"
-more-itertools = ">=4.0.0"
 packaging = "*"
-pluggy = ">=0.12,<1.0"
-py = ">=1.8.2"
-toml = "*"
-
-[package.dependencies.importlib-metadata]
-python = "<3.8"
-version = ">=0.12"
+pluggy = ">=0.12,<2.0"
+tomli = {version = ">=1.0.0", markers = "python_version < \"3.11\""}
 
 [package.extras]
-checkqa_mypy = ["mypy (0.780)"]
-testing = ["argcomplete", "hypothesis (>=3.56)", "mock", "nose", "requests", "xmlschema"]
+testing = ["argcomplete", "hypothesis (>=3.56)", "mock", "nose", "pygments (>=2.7.2)", "requests", "xmlschema"]
 
 [[package]]
-category = "dev"
-description = "Python 2 and 3 compatibility utilities"
 name = "six"
+version = "1.16.0"
+description = "Python 2 and 3 compatibility utilities"
+category = "dev"
 optional = false
 python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*"
-version = "1.15.0"
+files = [
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+]
 
 [[package]]
-category = "dev"
-description = "Sorted Containers -- Sorted List, Sorted Dict, Sorted Set"
 name = "sortedcontainers"
+version = "2.4.0"
+description = "Sorted Containers -- Sorted List, Sorted Dict, Sorted Set"
+category = "dev"
 optional = false
 python-versions = "*"
-version = "2.2.2"
+files = [
+    {file = "sortedcontainers-2.4.0-py2.py3-none-any.whl", hash = "sha256:a163dcaede0f1c021485e957a39245190e74249897e2ae4b2aa38595db237ee0"},
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+]
 
 [[package]]
-category = "dev"
-description = "ANSII Color formatting for output in terminal."
 name = "termcolor"
+version = "2.1.1"
+description = "ANSI color formatting for output in terminal"
+category = "dev"
 optional = false
-python-versions = "*"
-version = "1.1.0"
+python-versions = ">=3.7"
+files = [
+    {file = "termcolor-2.1.1-py3-none-any.whl", hash = "sha256:fa852e957f97252205e105dd55bbc23b419a70fec0085708fc0515e399f304fd"},
+    {file = "termcolor-2.1.1.tar.gz", hash = "sha256:67cee2009adc6449c650f6bcf3bdeed00c8ba53a8cda5362733c53e0a39fb70b"},
+]
+
+[package.extras]
+tests = ["pytest", "pytest-cov"]
 
 [[package]]
+name = "tomli"
+version = "2.0.1"
+description = "A lil' TOML parser"
 category = "dev"
-description = "Python Library for Tom's Obvious, Minimal Language"
-name = "toml"
 optional = false
-python-versions = "*"
-version = "0.10.1"
+python-versions = ">=3.7"
+files = [
+    {file = "tomli-2.0.1-py3-none-any.whl", hash = "sha256:939de3e7a6161af0c887ef91b7d41a53e7c5a1ca976325f429cb46ea9bc30ecc"},
+    {file = "tomli-2.0.1.tar.gz", hash = "sha256:de526c12914f0c550d15924c62d72abc48d6fe7364aa87328337a31007fe8a4f"},
+]
 
 [[package]]
+name = "typing-extensions"
+version = "4.4.0"
+description = "Backported and Experimental Type Hints for Python 3.7+"
 category = "dev"
-description = "A small Python utility to set file creation time on Windows"
-marker = "sys_platform == \"win32\""
+optional = false
+python-versions = ">=3.7"
+files = [
+    {file = "typing_extensions-4.4.0-py3-none-any.whl", hash = "sha256:16fa4864408f655d35ec496218b85f79b3437c829e93320c7c9215ccfd92489e"},
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+]
+
+[[package]]
 name = "win32-setctime"
+version = "1.1.0"
+description = "A small Python utility to set file creation time on Windows"
+category = "dev"
 optional = false
 python-versions = ">=3.5"
-version = "1.0.1"
+files = [
+    {file = "win32_setctime-1.1.0-py3-none-any.whl", hash = "sha256:231db239e959c2fe7eb1d7dc129f11172354f98361c4fa2d6d2d7e278baa8aad"},
+    {file = "win32_setctime-1.1.0.tar.gz", hash = "sha256:15cf5750465118d6929ae4de4eb46e8edae9a5634350c01ba582df868e932cb2"},
+]
 
 [package.extras]
-dev = ["pytest (>=4.6.2)", "black (>=19.3b0)"]
+dev = ["black (>=19.3b0)", "pytest (>=4.6.2)"]
 
 [[package]]
-category = "dev"
-description = "Backport of pathlib-compatible object wrapper for zip files"
-marker = "python_version < \"3.8\""
 name = "zipp"
+version = "3.11.0"
+description = "Backport of pathlib-compatible object wrapper for zip files"
+category = "dev"
 optional = false
-python-versions = ">=3.6"
-version = "3.1.0"
+python-versions = ">=3.7"
+files = [
+    {file = "zipp-3.11.0-py3-none-any.whl", hash = "sha256:83a28fcb75844b5c0cdaf5aa4003c2d728c77e05f5aeabe8e95e56727005fbaa"},
+    {file = "zipp-3.11.0.tar.gz", hash = "sha256:a7a22e05929290a67401440b39690ae6563279bced5f314609d9d03798f56766"},
+]
 
 [package.extras]
-docs = ["sphinx", "jaraco.packaging (>=3.2)", "rst.linker (>=1.9)"]
-testing = ["jaraco.itertools", "func-timeout"]
+docs = ["furo", "jaraco.packaging (>=9)", "jaraco.tidelift (>=1.4)", "rst.linker (>=1.9)", "sphinx (>=3.5)"]
+testing = ["flake8 (<5)", "func-timeout", "jaraco.functools", "jaraco.itertools", "more-itertools", "pytest (>=6)", "pytest-black (>=0.3.7)", "pytest-checkdocs (>=2.4)", "pytest-cov", "pytest-enabler (>=1.3)", "pytest-flake8", "pytest-mypy (>=0.9.1)"]
 
 [metadata]
-content-hash = "56f656eaeb0471f4b059ae3c3a1a259ee036a4a875d180b908cbb54327bea2c6"
-python-versions = "^3.6"
-
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-pytest = [
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-sortedcontainers = [
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-]
-toml = [
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-    {file = "toml-0.10.1.tar.gz", hash = "sha256:926b612be1e5ce0634a2ca03470f95169cf16f939018233a670519cb4ac58b0f"},
-]
-win32-setctime = [
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-    {file = "win32_setctime-1.0.1.tar.gz", hash = "sha256:b47e5023ec7f0b4962950902b15bc56464a380d869f59d27dbf9ab423b23e8f9"},
-]
-zipp = [
-    {file = "zipp-3.1.0-py3-none-any.whl", hash = "sha256:aa36550ff0c0b7ef7fa639055d797116ee891440eac1a56f378e2d3179e0320b"},
-    {file = "zipp-3.1.0.tar.gz", hash = "sha256:c599e4d75c98f6798c509911d08a22e6c021d074469042177c8c86fb92eefd96"},
-]
+lock-version = "2.0"
+python-versions = "^3.7"
+content-hash = "89365fe557cd87888c4381f25176c19c8bae28c217c89aaac2db05b33cc85f79"
diff --git a/python/pyproject.toml b/python/pyproject.toml
index faa8c0f..53e4eae 100644
--- a/python/pyproject.toml
+++ b/python/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "maturin"
 
 [tool.poetry]
 name = "pytextspan"
-version = "0.5.4"
+version = "0.5.5"
 description = ""
 authors = [ "Yohei Tamura <tamuhey@gmail.com>",]
 license = "MIT"
@@ -18,11 +18,11 @@ files = [ "src/lib.rs", "Cargo.toml",]
 tag_prefix = "python/"
 
 [tool.poetry.dependencies]
-python = "^3.6"
+python = "^3.7"
 
 [tool.poetry.dev-dependencies]
-pytest = "^6.0.1"
-hypothesis = "^5.23.11"
+pytest = "^7.2"
+hypothesis = "^6.61.0"
 pydoc-md = "^0.1.0"
 
 [tool.pytest.ini_options]
diff --git a/python/src/lib.rs b/python/src/lib.rs
index 895c457..01cea7c 100644
--- a/python/src/lib.rs
+++ b/python/src/lib.rs
@@ -1,5 +1,5 @@
 use pyo3::prelude::*;
-use textspan::Span;
+use textspanrs::Span;
 
 #[pymodule]
 fn textspan(_py: Python, m: &PyModule) -> PyResult<()> {
@@ -18,15 +18,15 @@ fn textspan(_py: Python, m: &PyModule) -> PyResult<()> {
     ///     >>> original_text = "FOo.BåR baZ";
     ///     >>> textspan.align_spans(spans, text, original_text)
     ///     [[(0, 3)], [(4, 7)]]
-    #[pyfn(m, "align_spans")]
-    #[text_signature = "(spans, text, original_text)"]
+    #[pyfn(m)]
+    #[pyo3(text_signature = "(spans, text, original_text)")]
     pub fn align_spans(
         _py: Python,
         spans: Vec<Span>,
         text: &str,
         original_text: &str,
     ) -> PyResult<Vec<Vec<Span>>> {
-        Ok(textspan::align_spans(&spans, text, original_text))
+        Ok(textspanrs::align_spans(&spans, text, original_text))
     }
 
     /// Converts the spans by the given `mapping`.
@@ -43,14 +43,14 @@ fn textspan(_py: Python, m: &PyModule) -> PyResult<()> {
     ///     >>> mapping = [[0, 1], [], [2], [4, 5, 6]]
     ///     >>> textspan.align_spans_by_mapping(spans, mapping)
     ///     [[(0, 2)], [(4, 7)]]
-    #[pyfn(m, "align_spans_by_mapping")]
-    #[text_signature = "(spans, mapping)"]
+    #[pyfn(m)]
+    #[pyo3(text_signature = "(spans, mapping)")]
     pub fn align_spans_by_mapping(
         _py: Python,
         spans: Vec<Span>,
         mapping: Vec<Vec<usize>>,
     ) -> PyResult<Vec<Vec<Span>>> {
-        Ok(textspan::align_spans_by_mapping(&spans, &mapping))
+        Ok(textspanrs::align_spans_by_mapping(&spans, &mapping))
     }
 
     /// Returns the span indices of `original_text` from the tokens based on the shortest edit script (SES).
@@ -64,14 +64,14 @@ fn textspan(_py: Python, m: &PyModule) -> PyResult<()> {
     ///     >>> textspan.get_original_spans(tokens, "FO.o  BåR")
     ///     [[(0, 2), (3, 4)], [(6, 9)]]
     ///
-    #[pyfn(m, "get_original_spans")]
-    #[text_signature = "(tokens, original_text)"]
+    #[pyfn(m)]
+    #[pyo3(text_signature = "(tokens, original_text)")]
     pub fn get_original_spans(
         _py: Python,
         tokens: Vec<&str>,
         original_text: &str,
     ) -> PyResult<Vec<Vec<Span>>> {
-        Ok(textspan::get_original_spans(&tokens, original_text))
+        Ok(textspanrs::get_original_spans(&tokens, original_text))
     }
 
     /// Remove overlapping spans from given `spans`.
@@ -86,10 +86,10 @@ fn textspan(_py: Python, m: &PyModule) -> PyResult<()> {
     ///     >>> assert textspan.remove_span_overlaps(spans) == [(0, 3), (5, 7)]
     ///
     ///
-    #[pyfn(m, "remove_span_overlaps")]
-    #[text_signature = "(spans)"]
+    #[pyfn(m)]
+    #[pyo3(text_signature = "(spans)")]
     pub fn remove_span_overlaps(_py: Python, spans: Vec<Span>) -> PyResult<Vec<Span>> {
-        Ok(textspan::remove_span_overlaps(&spans))
+        Ok(textspanrs::remove_span_overlaps(&spans))
     }
 
     /// Remove overlapping spans from given `spans`, and returns remained span indices.
@@ -104,10 +104,10 @@ fn textspan(_py: Python, m: &PyModule) -> PyResult<()> {
     ///     >>> assert textspan.remove_span_overlaps_idx(spans) == [1, 3]
     ///
     ///
-    #[pyfn(m, "remove_span_overlaps_idx")]
-    #[text_signature = "(spans)"]
+    #[pyfn(m)]
+    #[pyo3(text_signature = "(spans)")]
     pub fn remove_span_overlaps_idx(_py: Python, spans: Vec<Span>) -> PyResult<Vec<usize>> {
-        Ok(textspan::remove_span_overlaps_idx(&spans))
+        Ok(textspanrs::remove_span_overlaps_idx(&spans))
     }
 
     fn to_tuple<T>(x: Result<T, T>) -> (T, bool) {
@@ -121,25 +121,25 @@ fn textspan(_py: Python, m: &PyModule) -> PyResult<()> {
     ///     >>> import textspan
     ///     >>> spans = [(0, 3), (3, 4), (4, 9), (9, 12)]
     ///     >>> assert textspan.lift_spans_index((2, 10), spans) == (0, 4)
-    #[pyfn(m, "lift_span_index")]
-    #[text_signature = "(span, target_spans)"]
+    #[pyfn(m)]
+    #[pyo3(text_signature = "(span, target_spans)")]
     pub fn lift_span_index(
         _py: Python,
         span: Span,
         target_spans: Vec<Span>,
     ) -> PyResult<((usize, bool), (usize, bool))> {
-        let (l, r) = textspan::lift_span_index(span, &target_spans);
+        let (l, r) = textspanrs::lift_span_index(span, &target_spans);
         Ok((to_tuple(l), to_tuple(r)))
     }
 
-    #[pyfn(m, "lift_spans_index")]
-    #[text_signature = "(spans, target_spans)"]
+    #[pyfn(m)]
+    #[pyo3(text_signature = "(spans, target_spans)")]
     pub fn lift_spans_index(
         _py: Python,
         spans: Vec<Span>,
         target_spans: Vec<Span>,
     ) -> PyResult<Vec<((usize, bool), (usize, bool))>> {
-        Ok(textspan::lift_spans_index(&spans, &target_spans)
+        Ok(textspanrs::lift_spans_index(&spans, &target_spans)
             .into_iter()
             .map(|(l, r)| (to_tuple(l), to_tuple(r)))
             .collect())
diff --git a/src/lib.rs b/src/lib.rs
index b62b989..adcc609 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -88,13 +88,13 @@ pub fn align_spans_by_mapping<T: AsRef<[usize]>>(spans: &[Span], mapping: &[T])
         let mut pret = vec![];
         for item in mapping.iter().take(end).skip(start) {
             for &y in item.as_ref() {
-                if prevy != None && prevy.unwrap() + 1 < y {
+                if prevy.is_some() && prevy.unwrap() + 1 < y {
                     pret.push((l.unwrap(), r.unwrap()));
                     l = None;
                 } else {
                     r = Some(y + 1);
                 }
-                if l == None {
+                if l.is_none() {
                     l = Some(y);
                     r = Some(y + 1);
                 }
@@ -432,7 +432,7 @@ mod tests {
             let rev = |x: usize| mapping.iter().position(|y| y.contains(&x)).unwrap();
             let l = rev(ret[0][0].0);
             assert!(
-                mapping[start].is_empty() || mapping[l].iter().any(|x| mapping[start].contains(&x)),
+                mapping[start].is_empty() || mapping[l].iter().any(|x| mapping[start].contains(x)),
                 "compare start.
                 ret: {:?}
                 l  : {}
@@ -444,7 +444,7 @@ mod tests {
             let r = rev(ret[ret.len() - 1][ret[0].len() - 1].1 - 1);
             assert!(
                 mapping[end - 1].is_empty()
-                    || mapping[end - 1].iter().any(|x| mapping[r].contains(&x)),
+                    || mapping[end - 1].iter().any(|x| mapping[r].contains(x)),
                 "compare end
             ret: {:?}
             r  : {}