code: def write_waypoint(self, latitude=None, longitude=None, description=None):
          
  
          if not description:
              description = ''
  
          latitude = self.format_latitude(latitude)
          longitude = self.format_longitude(longitude)
  
          self.write_config(
              'ADDWP', '%s,%s,%s' % (latitude, longitude, description[0:50])
          )
docs: Adds a waypoint to the current task declaration. The first and the
          last waypoint added will be treated as takeoff and landing location,
          respectively.
  
          ::
  
              writer.write_waypoint(
                  latitude=(51 + 7.345 / 60.),
                  longitude=(6 + 24.765 / 60.),
                  text='Meiersberg',
              )
              # -> $PFLAC,S,ADDWP,5107345N,00624765E,Meiersberg
  
          If no ``latitude`` or ``longitude`` is passed, the fields will be
          filled with zeros (i.e. unknown coordinates). This however should only
          be used for takeoff  and landing points.
  
          :param latitude: latitude of the point (between -90 and 90 degrees)
          :param longitude: longitude of the point (between -180 and 180 degrees)
          :param description: arbitrary text description of waypoint