'Check to see if frames are the same.
= ERROR CONDITIONS
- If the frame of the rhs Duration is not the same as our frame,
an error is thrown.
= INPUT VARIABLES
- rhs    The Duration to check for the same frame
- func   The name of the function doing the check.'

def checkSameFrame(self, rhs, func):

    if (self._frame != rhs._frame):
        msg = (u"Cannot    %s    Duration's    with    different    frames.\nLHS:    %s\nRHS:    %s" % (func, self._frame, rhs._frame))
        raise ValueError(msg)
