more pep8 fixes

_pytest/monkeypatch.py

@@ -193,12 +193,12 @@ class monkeypatch:
         undo stack. Calling it a second time has no effect unless
         you do more monkeypatching after the undo call.
         
-        There is generally no need to call `undo()`, since it is 
+        There is generally no need to call `undo()`, since it is
         called automatically during tear-down.
         
         Note that the same `monkeypatch` fixture is used across a
         single test function invocation. If `monkeypatch` is used both by
-        the test function itself and one of the test fixtures, 
+        the test function itself and one of the test fixtures,
         calling `undo()` will undo all of the changes made in
         both functions.
         """