docs: def _is_process_filtered(self, process, key=None):
          """Return True if the process[key] should be filtered according to the current filter"""
          if key is None:
              key = self.filter_key
          try:
              # If the item process[key] is a list, convert it to a string
              # in order to match it with the current regular expression
              if isinstance(process[key], list):
                  value = ' '.join(process[key])
              else:
                  value = process[key]
          except KeyError:
              # If the key did not exist
              return False
          try:
              return self._filter_re.match(value) is None
          except (AttributeError, TypeError):
              # AttributeError
              # Filter processes crashs with a bad regular expression pattern (issue #665)
              # TypeError
              # Filter processes crashs if value is None (issue #1105)
              return False