Description of problem:
just tried to use poman-compose with docker-compose file

Version-Release number of selected component:
podman-compose-0.1.5-2.git20191107.fc31

Additional info:
reporter:       libreport-2.12.0
cgroup:         0::/user.slice/user-1000.slice/user/gnome-terminal-server.service
cmdline:        /usr/bin/python3 /usr/bin/podman-compose up
crash_function: flat_deps
exception_type: AttributeError
executable:     /usr/bin/podman-compose
interpreter:    python3-3.7.6-2.fc31.x86_64
kernel:         5.5.17-200.fc31.x86_64
runlevel:       N 5
type:           Python3
uid:            1000

Truncated backtrace:
podman_compose.py:603:flat_deps:AttributeError: 'NoneType' object has no attribute 'items'

Traceback (most recent call last):
  File "/usr/bin/podman-compose", line 11, in <module>
    load_entry_point('podman-compose==0.1.6.dev0', 'console_scripts', 'podman-compose')()
  File "/usr/lib/python3.7/site-packages/podman_compose.py", line 1267, in main
    podman_compose.run()
  File "/usr/lib/python3.7/site-packages/podman_compose.py", line 741, in run
    self._parse_compose_file()
  File "/usr/lib/python3.7/site-packages/podman_compose.py", line 822, in _parse_compose_file
    flat_deps(services, with_extends=True)
  File "/usr/lib/python3.7/site-packages/podman_compose.py", line 603, in flat_deps
    for name, srv in services.items():
AttributeError: 'NoneType' object has no attribute 'items'

Local variables in innermost frame:
services: None
with_extends: True