def ensure_geo_reference(origin):
 if isinstance(origin, Geo_reference):
  geo_ref = origin
 elif (origin is None):
  geo_ref = None
 else:
  geo_ref = apply(Geo_reference, origin)
 return geo_ref

def ensure_geo_reference ( origin ) : if isinstance ( origin , Geo_reference ) : geo_ref = origin elif ( origin is None ) : geo_ref = None else : geo_ref = apply ( Geo_reference , origin ) return geo_ref
given a list/tuple of zone .