code: def ApproximateDistanceBetweenPoints(pa, pb):
    
    alat, alon = pa
    blat, blon = pb
    sa = transitfeed.Stop(lat=alat, lng=alon)
    sb = transitfeed.Stop(lat=blat, lng=blon)
    return transitfeed.ApproximateDistanceBetweenStops(sa, sb)
docs: Finds the distance between two points on the Earth's surface.
  
    This is an approximate distance based on assuming that the Earth is a sphere.
    The points are specified by their lattitude and longitude.
  
    Args:
      pa: the first (lat, lon) point tuple
      pb: the second (lat, lon) point tuple
  
    Returns:
      The distance as a float in metres.