DNF commands are not working, failing with "AttributeError: 'Process' object has no attribute 'parents'"

Issue

• Whenever any dnf command is run, it fails and displays the following error:

  Updating Subscription Management repositories.
  Traceback (most recent call last):
  File "/usr/bin/dnf", line 62, in <module>
      main.user_main(sys.argv[1:], exit_code=True)
  File "/usr/lib/python3.6/site-packages/dnf/cli/main.py", line 201, in user_main
      errcode = main(args)
  File "/usr/lib/python3.6/site-packages/dnf/cli/main.py", line 67, in main
      return _main(base, args, cli_class, option_parser_class)
  File "/usr/lib/python3.6/site-packages/dnf/cli/main.py", line 102, in _main
      cli.configure(list(map(ucd, args)), option_parser())
  File "/usr/lib/python3.6/site-packages/dnf/cli/cli.py", line 830, in configure
      self.base.init_plugins(opts.disableplugin, opts.enableplugin, self)
  File "/usr/lib/python3.6/site-packages/dnf/base.py", line 307, in init_plugins
      self._plugins._run_init(self, cli)
  File "/usr/lib/python3.6/site-packages/dnf/plugin.py", line 154, in _run_init
      plugin = p_cls(base, cli)
  File "/usr/lib/python3.6/site-packages/dnf-plugins/perfmetrics.py", line 81, in __init__
      reversed([proc.name()] + [p.name() for p in proc.parents()])
  AttributeError: 'Process' object has no attribute 'parents'