You seem to have usage examples in your documentation strings. It is a good idea to test that
they work, if you make any modification to the code. Also they work as a unit tests for your code. This can be done by using your module in the interpreter and then copy pasting the output of the interpreter directly to your documentation string. You can add a new file to your project, which runs your tests.

test.py:

if __name__ == "__main__":
    import doctest
    import f_stats
    globs = {
        'f_stats': f_stats
    }

    doctest.testfile(filename="f_stats.py",  globs=globs)

See https://docs.python.org/3/library/doctest.html?highlight=doctest#module-doctest

I'm sorry python is so stupid there is no multiline commenting. It makes these examples pretty hard to run.

Use:
""" your
multi
line
comment
"""

See https://www.python.org/dev/peps/pep-0257/