pep8 on printing.py

theano/printing.py

@@ -1298,7 +1298,7 @@ def hex_digest(x):
             raise RuntimeError("Can't run hex_digest"
                                "because hashlib is not available.")
     assert isinstance(x, np.ndarray)
-    rval = hashlib.md5(x.tostring).hexdigest()
+    rval = hashlib.md5(x.tostring()).hexdigest()
     # hex digest must be annotated with strides to avoid collisions
     # because the buffer interface only exposes the raw data, not
     # any info about the semantics of how that data should be arranged