What is the typical cause of a 'cph standard error' in Python when using the `cph` library?

The 'cph standard error' in Python using the `cph` library often indicates a problem with the input data. Specifically, it frequently arises when the input data doesn't meet the expected format or constraints for the chosen model (e.g., missing values, incorrect data types, or data outside the expected range). It's crucial to validate your input data thoroughly before passing it to the `cph` function. Check for inconsistencies and outliers. Also, ensure the data is properly preprocessed.