code: def length(self):
          
          return math.sqrt(
              (self.endpoint_a.northing - self.endpoint_b.northing) ** 2 +
              (self.endpoint_a.easting - self.endpoint_b.easting) ** 2
          )
docs: Return length(meter) of the line
  
          :return: length(meter) of the line
          :rtype: float