Source: 📖 Effective Python item 89

The warnings module explained

The warnings module can be used to warn callers of your code that their present usage will soon be out of date, and they should update their code to meet new standards to prevent their code from breaking in the near future. The module is imported like any other warning, and warnings can be raised using the following syntax:

import warnings

if arbitrary_condition:
	warnings.warn('this is my warning', DeprecationWarning)

This will raise a DepracationWarning at runtime—the code still runs, but a warning is printed to the console. This will encourage callers to update their code to prevent future breakages.