Update cumsum.py

Author: sophiagu

tensorflow_probability/python/bijectors/cumsum.py

@@ -117,5 +117,5 @@ def _forward_log_det_jacobian(self, x):
     return tf.constant(0., x.dtype)
 
   @property
-  def _compposite_tensor_shape_params(self):
+  def _composite_tensor_shape_params(self):
     return ('axis',)