flake8 for doc (it's cleaner).

doc/tutorial/gradients.txt

@@ -124,7 +124,7 @@ do is to loop over the entries in *y* and compute the gradient of
 >>> import theano.tensor as T
 >>> x = T.dvector('x')
 >>> y = x ** 2
->>> J, updates = theano.scan(lambda i, y,x : T.grad(y[i], x), sequences=T.arange(y.shape[0]), non_sequences=[y,x])
+>>> J, updates = theano.scan(lambda i, y, x : T.grad(y[i], x), sequences=T.arange(y.shape[0]), non_sequences=[y, x])
 >>> f = theano.function([x], J, updates=updates)
 >>> f([4, 4])
 array([[ 8.,  0.],