'Initialize an Affine transform from a 3x3 numpy float array::
a c e
b d f
0 0 1
If *matrix* is None, initialize with the identity transform.'

def __init__(self, matrix=None, **kwargs):

    Affine2DBase.__init__(self, **kwargs)
    if (matrix is None):
        matrix = np.identity(3)
    elif DEBUG:
        matrix = np.asarray(matrix, float)
        assert (matrix.shape == (3, 3))
    self._mtx = matrix
    self._invalid = 0
