<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def mate_bottom(self):
        " connect to the bottom of the cup"
        return Mate(self, CoordSystem(\
            origin=(0, 0, -self.height),\
            xDir=(1, 0, 0),\
            normal=(0, 0, 1)))