Error building wheels for PyGObject while deploying flask in heroku

I'm trying to deploy my Flask app on Heroku and keep getting this error:

       Failed to build dbus-python PyGObject
       ERROR: Could not build wheels for PyGObject which use PEP 517 and cannot be installed directly
 !     Push rejected, failed to compile Python app.
 !     Push failed

I've googled it but can't find anything. How can I fix this?