docs: def tag(self, *tags):
          """
          Tags the job with one or more unique indentifiers.
  
          Tags must be hashable. Duplicate tags are discarded.
  
          :param tags: A unique list of ``Hashable`` tags.
          :return: The invoked job instance
          """
          if not all(isinstance(tag, collections.Hashable) for tag in tags):
              raise TypeError('Tags must be hashable')
          self.tags.update(tags)
          return self