code: def first(self):
          
          def _transform(xs):  # pylint: disable=missing-docstring, invalid-name
              try:
                  return [six.next(iter(xs))]
              except StopIteration:
                  return []
  
          return self.transform(_transform, 'first')
docs: Return a Query that selects only the first element of this Query.
          If no elements are available, returns a query with no results.
  
          Example usage:
  
          .. code:: python
  
              >> q = Query(lambda: list(range(5)))
              >> q.first.results
              [0]
  
          Returns:
              Query