code: def partLon(ID, chart):
      
      # Get diurnal or nocturnal formula
      abc = FORMULAS[ID][0] if chart.isDiurnal() else FORMULAS[ID][1]
      a = objLon(abc[0], chart)
      b = objLon(abc[1], chart)
      c = objLon(abc[2], chart)
      return c + b - a
docs: Returns the longitude of an arabic part.