I have a package with a few modules, each module has a class (or a few classes) defined within it. I need to get the list of all modules within the package. Is there an API for this in python?

Here is the file structure:

\pkg\
\pkg\__init__.py
\pkg\module1.py -> defines Class1
\pkg\module2.py -> defines Class2
\pkg\module3.py -> defines Class3 and Class31

from within module1 I need to get the list of modules within pkg, and then import all the classes defined in these modules

Thanks ak