E713: false negatives

[rkday]

I was looking into https://github.com/jcrocholl/pep8/issues/330, and I noticed that the following don't cause E713 when they should:

if not (X) in Y:
    pass

if not X() in Y:
    pass

Looks like the regular expression is picking up the ( between not and in and wrongly deciding that this is something of the form:

if not (X in Y or X is Z):
    pass