code: def attrs(self, attribute_name):
          
          desc = u'attrs({!r})'.format(attribute_name)
          return self.map(lambda el: el.get_attribute(attribute_name), desc).results
docs: Retrieve HTML attribute values from the elements matched by the query.
  
          Example usage:
  
          .. code:: python
  
              # Assume that the query matches html elements:
              # <div class="foo"> and <div class="bar">
              >> q.attrs('class')
              ['foo', 'bar']
  
          Args:
              attribute_name (str): The name of the attribute values to retrieve.
  
          Returns:
              A list of attribute values for `attribute_name`.