code: def mate_bottom(self):
          " bottom of the stator"
          return Mate(self, CoordSystem(
              origin=(0, 0, -self.length/2),
              xDir=(1, 0, 0),
              normal=(0, 0, -1)
              )f mate_bottom(self):
          " bottom of the stator"
          return Mate(self, CoordSystem(
              origin=(0, 0, -self.length/2),
              xDir=(1, 0, 0),
              normal=(0, 0, -1)
              ))
docs: bottom of the stator