def __hash__(self):
        '''hash method allows use of Dims as dict key.
        Manually modifying Dim attributes will break the dict
        so don't do that!'''
        return hash(self.value)^reduce( 
              lambda x,y: x^y, [hash(item) for item in self.dims.items()],0)
hash method allows use of Dims as dict key.
        Manually modifying Dim attributes will break the dict
        so don't do that!
recipes/Python/577333_Numerical_type_units/recipe-577333.py