test_gradient.py has been modified in order to respect the flake8 style.

theano/sandbox/cuda/tests/test_gradient.py

@@ -8,7 +8,7 @@ from theano.sandbox import cuda
 # Skip test if cuda_ndarray is not available.
 from nose.plugins.skip import SkipTest
 import theano.sandbox.cuda as cuda_ndarray
-if cuda_ndarray.cuda_available == False:
+if cuda_ndarray.cuda_available is False:
     raise SkipTest('Optional package cuda disabled')