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

def checkSameUnits(self, rhs, func):

    if (self._units != rhs._units):
        msg = (u'Cannot    %s    units    of    different    types.\nLHS:    %s\nRHS:    %s' % (func, self._units, rhs._units))
        raise ValueError(msg)
