'Validate the absence of disallowed headers for "unsafe" operations.
:returns: None for safe operations or swob.HTTPBadResponse if the
request includes disallowed headers.'

def _clean_disallowed_headers(self, env, start_response):

    if (env['REQUEST_METHOD'] in ('GET', 'HEAD', 'OPTIONS')):
        return
    for h in env:
        if (h in self.disallowed_headers):
            return HTTPBadRequest(body=('The    header    %r    is    not    allowed    in    this    tempurl' % h[len('HTTP_'):].title().replace('_', '-')))(env, start_response)
