docs: def get_display_name(entity):
      """
      Gets the display name for the given entity, if it's an :tl:`User`,
      :tl:`Chat` or :tl:`Channel`. Returns an empty string otherwise.
      """
      if isinstance(entity, types.User):
          if entity.last_name and entity.first_name:
              return '{} {}'.format(entity.first_name, entity.last_name)
          elif entity.first_name:
              return entity.first_name
          elif entity.last_name:
              return entity.last_name
          else:
              return ''
  
      elif isinstance(entity, (types.Chat, types.Channel)):
          return entity.title
  
      return ''