def inv(self):
        """The inverse transformation"""
        result = Complete(self.r.transpose(), np.dot(self.r.transpose(), -self.t))
        result._cache_inv = self
        return result
def inv ( self ) : result = Complete ( self . r . transpose ( ) , np . dot ( self . r . transpose ( ) , - self . t ) ) result . _cache_inv = self return result
The inverse transformation