<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def distance(self, other):
 """ Distance between points Args: other (:obj:`Point`) Returns: float: Distance in km """

        return distance(self.lat, self.lon, None, other.lat, other.lon, None)