def __init__(self, matrix = None):
Affine2DBase.__init__(self)<EOL>if matrix is None:<EOL><INDENT>matrix = np.identity(<NUM_LIT:3>)<EOL><DEDENT>elif DEBUG:<EOL><INDENT>matrix = np.asarray(matrix, np.float_)<EOL>assert matrix.shape == (<NUM_LIT:3>, <NUM_LIT:3>)<EOL><DEDENT>self._mtx = matrix<EOL>self._invalid = <NUM_LIT:0><EOL>
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.