Model inference must explicitly specify start and end times in current version

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In the current version model inference must explicitly specify the start and end times, otherwise an error will be raised. Because loaded_model proxies the predict() method of the detector, if you don't explicitly specify the start or end time, the values of the "start_time" and " end_time" fields in the params dictionary will be automatically rewritten as "string" before calling the predict() method of the model, which will result in an error when validating the data format.