Raise warning in Python without interrupting program

Solution 1:

import warnings
warnings.warn("Warning...........Message")

See the python documentation: here

Solution 2:

You shouldn't raise the warning, you should be using warnings module. By raising it you're generating error, rather than warning.

Solution 3:

By default, unlike an exception, a warning doesn't interrupt.

After import warnings, it is possible to specify a Warnings class when generating a warning. If one is not specified, it is literally UserWarning by default.

>>> warnings.warn('This is a default warning.')
<string>:1: UserWarning: This is a default warning.

To simply use a preexisting class instead, e.g. DeprecationWarning:

>>> warnings.warn('This is a particular warning.', DeprecationWarning)
<string>:1: DeprecationWarning: This is a particular warning.

Creating a custom warning class is similar to creating a custom exception class:

>>> class MyCustomWarning(UserWarning):
...     pass
... 
... warnings.warn('This is my custom warning.', MyCustomWarning)

<string>:1: MyCustomWarning: This is my custom warning.

For testing, consider assertWarns or assertWarnsRegex.

As an alternative, especially for standalone applications, consider the logging module. It can log messages having a level of debug, info, warning, error, etc. Log messages having a level of warning or higher are by default printed to stderr.