flake8 gradient.py

theano/gradient.py

@@ -1676,7 +1676,7 @@ def verify_grad(fun, pt, n_tests=2, rng=None, eps=None,
     cost = theano.tensor.sum(t_r * o_output)
 
     if no_debug_ref:
-        mode_for_cost=mode_not_debug(mode)
+        mode_for_cost = mode_not_debug(mode)
         cost_fn = function(tensor_pt, cost, name='gradient.py cost',
                            mode=mode_for_cost)
     else: