'Checks whether the required parameters are either in the HTTP
``Authorization`` header sent by some clients (the preferred method
according to OAuth spec) or fall back to ``GET/POST``.'

def is_valid_request(self, request):

    auth_params = request.META.get(u'HTTP_AUTHORIZATION', [])
    return (self.is_in(auth_params) or self.is_in(request.POST) or self.is_in(request.GET))
