docs: def check_plugins(self):
          """ collect plugins from entry point 'frosted.plugins'
  
          and run their check() method, passing the filename
          """
          checkers = {}
          for ep in pkg_resources.iter_entry_points(group='frosted.plugins'):
              checkers.update({ep.name: ep.load()})
  
          for plugin_name, plugin in checkers.items():
              if self.filename != '(none)':
                  messages = plugin.check(self.filename)
                  for message, loc, args, kwargs in messages:
                      self.report(message, loc, *args, **kwargs)