fix format

python/paddle/fluid/backward.py

@@ -1313,8 +1313,8 @@ def _append_backward_vars_(block, start_op_idx, grad_to_var, grad_info_map):
             if grad_var_ins:
                 existing_grad_var_ins = [
                     var for var in grad_var_ins
-                    if block.desc.has_var_recursive(cpt.to_bytes(var)) or
-                    var in parent_op_vars
+                    if block.desc.has_var_recursive(cpt.to_bytes(var)) or var in
+                    parent_op_vars
                 ]
                 if not existing_grad_var_ins:
                     '''

python/paddle/fluid/tests/unittests/gradient_checker.py

@@ -312,7 +312,7 @@ def grad_check(x,
             _compute_analytical_jacobian(prog, clone_x, clone_y, place, scope))
 
     for i, (x_idx,
-            y_idx) in enumerate(product(* [range(len(x)), range(len(y))])):
+            y_idx) in enumerate(product(*[range(len(x)), range(len(y))])):
         a = analytical[y_idx][x_idx]
         n = numerical[x_idx][y_idx]
         if not np.allclose(a, n, rtol, atol):