Python, how to enable all warnings?

Question

I was setting up a ImportWarning as seemed appropriate but noticed this warning is not reported by default;

How can I set python to report ImportWarning or all warnings?

Here is the import warning i wrote:

try:
    from markdown import markdown

except ImportError, err:
    warnings.warn(
        'Unable to load Pypi package `markdown`, HTML output will be unavailable. {}'.format(err),
        ImportWarning
    )

Answer 1

To enable warnings run python with the -Wdefault or -Wd switch.

Answer 2

import warnings
warnings.simplefilter('module')

Or:

import warnings
warnings.simplefilter('always')

The list of filters are in the docs

Answer 3

You can also enable warnings for just one section of code:

import warnings
with warnings.catch_warnings():
    warnings.simplefilter('always')
    # all warnings here are enabled
# warnings here are left as default (probably silent)