add summatory

Author: Jolinator

Diff for: Summatory.py

@@ -0,0 +1,8 @@
+def suma(slist): #  SUMMATORY
+    sum = 0
+    for x in slist: 
+        if not (type(x) == int and type(x) == float): 
+            sum += x
+        else:
+            raise ValueError("Item in list wasn't a number")
+    return sum