Generating sphinx documentation for ROS package - No module named '..'

Question

I am trying to generate sphinx docs for some python modules in a ROS package, but I encountered an issue where the autodoc does not find some of the imports. The imports in question are generated from action definitions:

from dialogflow_actions.msg import (
    TurnToHumanAction,
    TurnToHumanFeedback,
    TurnToHumanResult,
)

I get an error saying that the package is not found:

WARNING: autodoc: failed to import module u'turn_to_human_action_client' from module u'dialogflow_actions.clients'; the following exception was raised:
No module named msg

I tried adding the path to the generated modules to conf.py:

sys.path.insert(0, os.path.abspath('/home/wstyczen/tiago_public_ws/devel/lib/python2.7/dist-packages/dialogflow_actions'))

and adding an .rst for those generated modules, but it does not help - still an error that the module is not found.

Has anyone had a similar issue? I couldn't find a solution anywhere and right now it does not generate the documentation for any of the files with similar imports. Thanks!