root@ip-172-31-103-28:/var/lib/juju/agents/unit-filebeat-12/charm# ./hooks/install 
Traceback (most recent call last):
  File "./hooks/install", line 19, in <module>
    main()
  File "/usr/local/lib/python3.5/dist-packages/charms/reactive/__init__.py", line 96, in main
    hookenv._run_atstart()
  File "/usr/local/lib/python3.5/dist-packages/charmhelpers/core/hookenv.py", line 1070, in _run_atstart
    callback(*args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/charms/reactive/altrelations.py", line 107, in _startup
    if not issubclass(relf, cls):
TypeError: issubclass() arg 1 must be a class