docs: def speed(self):
          """Calculate speed between :class:`Points`.
  
          Returns:
              list of float: Speed between :class:`Point` elements in km/h
          """
          if not len(self) > 1:
              raise RuntimeError('More than one location is required')
          try:
              times = [i.time for i in self]
          except AttributeError:
              raise NotImplementedError('Not all Point objects include time '
                                        'attribute')
  
          return (distance / ((times[i + 1] - times[i]).seconds / 3600)
                  for i, distance in enumerate(self.distance()))