183 – Deprecation warnings

Use the decorator warnings.deprecated to issue a deprecation warning when certain functions, methods, or classes are used:

from warnings import deprecated

@deprecated("Use bar instead.")
def foo():
    pass

def bar():
    pass

foo()
# DeprecationWarning: Use bar instead.

The code above shows that calling foo will issue a deprecation warning, since the function foo was decorated with the decorator deprecated.

Similarly, you can apply the decorator deprecated to a class:

from warnings import deprecated

@deprecated("Use D instead.")
class C:
    pass
    
class D:
    pass
    
c = C()
# DeprecationWarning: Use D instead.