code: def set_polygon_offset(self, factor=0., units=0.):
          
          self.glir.command('FUNC', 'glPolygonOffset', float(factor),
                            float(units))
docs: Set the scale and units used to calculate depth values
      
          Parameters
          ----------
          factor : float
              Scale factor used to create a variable depth offset for
              each polygon.
          units : float
              Multiplied by an implementation-specific value to create a
              constant depth offset.