Python: Import a Submodule Programmatically

Situation:
In Python 2.7, there is a need to import a sub-package programmatically by name.

Problem:
I've looked at __import__ and importlib but the solution is not readily apparent.

Solution:

import importlib

module_name = '.'.join(('os','path'))
path = importlib.import_module(module_name)

#or

import sys

module_name = '.'.join(('os','path'))

__import__(module_name)
path = sys.modules[module_name]

References:

1.  importlib – Convenience wrappers for __import__()
2. Source code for importlib