How do I get the docstring from a calling module?

Question

Can I get the __doc__ string of the main script?

Here is the starting script, which would be run from command line: python a.py

module a.py

import b
b.func()

module b.py

def func():
    ???.__doc__

How can I get the calling module, as an object?

I am not asking about how to get the file name as string. I know how to retrieve the file's name from stack trace. I don't want to retrieve the doc string by parsing manually. Also, I don't think I can just import by m = __import__(a) because of circular import loop.

Answer 1

a.py

"""
Foo bar
"""

import b
if __name__ == '__main__':
    b.show_your_docs()

b.py

def show_your_docs():
    name = caller_name(1)
    print(__import__(name).__doc__)

Where caller_name is code from this gist

The weakness of this approach though is it is getting a string representation of the module name and reimporting it, instead of getting a reference to the module (type).