def authenticate(self, request):
        """
        Returns two-tuple of (user, token) if authentication succeeds,
        or None otherwise.
        """

        auth = get_authorization_header(request).split()

        if len(auth) == 1:
            msg = 'Invalid bearer header. No credentials provided.'
            raise exceptions.AuthenticationFailed(msg)
        elif len(auth) > 2:
            msg = 'Invalid bearer header. Token string should not contain spaces.'
            raise exceptions.AuthenticationFailed(msg)

        if auth and auth[0].lower() == b'bearer':
            access_token = auth[1]
        elif request.POST in 'access_token':
            access_token = request.POST['access_token']
        elif 'access_token' in request.GET and self.allow_query_params_token:
            access_token = request.GET['access_token']
        else:
            return None

        return self.authenticate_credentials(request, access_token)
dataset/ETHPy150Open jpadilla/django-rest-framework-oauth/rest_framework_oauth/authentication.py/OAuth2Authentication.authenticate/swapped operands of `in`