Traceback (most recent call last):
  File "/home/michael/.local/lib/python3.6/site-packages/pafy/pafy.py", line 48, in <module>
    import youtube_dl
ModuleNotFoundError: No module named 'youtube_dl'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "l_?.py", line 2, in <module>
    import pafy
  File "/home/michael/.local/lib/python3.6/site-packages/pafy/__init__.py", line 7, in <module>
    from .pafy import new
  File "/home/michael/.local/lib/python3.6/site-packages/pafy/pafy.py", line 52, in <module>
    "pafy: youtube-dl not found; you can use the internal backend by "
ImportError: pafy: youtube-dl not found; you can use the internal backend by setting the environmental variable PAFY_BACKEND to "internal". It is not enabled by default because it is not as well maintained as the youtube-dl backend.