def __iadd__(self, mat):
        """ Add a matrix to this matrix.
        This modifies the current matrix """

        # Calls __add__
        tempmat = self + mat
        self.rows = tempmat.rows[:]
        return self
 Add a matrix to this matrix.
        This modifies the current matrix 
recipes/Python/578131_A_simple_Matrix_class/recipe-578131.py