remove print in test and pep8 fix.

theano/gradient.py

@@ -464,7 +464,7 @@ def grad(cost, wrt, consider_constant=None,
         known_grads = OrderedDict()
     else:
         m = "known_grads must be an OrderedDict. "
-        assert isinstance(known_grads, OrderedDict) or len(known_grads) <=1, m
+        assert isinstance(known_grads, OrderedDict) or len(known_grads) <= 1, m
 
     # The gradient of the cost is 1 unless specified otherwise by known_grads.
     if cost is not None:

theano/tests/test_gradient.py

@@ -472,7 +472,6 @@ def test_known_grads():
     true_grads = true_grads(*values)
 
     for layer in layers:
-        print('Testing by separately computing ', layer)
         first = theano.tensor.grad(cost, layer, disconnected_inputs='ignore')
         known = OrderedDict(izip(layer, first))
         full = theano.tensor.grad(cost=None, known_grads=known, wrt=inputs, disconnected_inputs='ignore')