def is_user_reseller_admin(self, req, account, user):
        """Returns True if the user is a .reseller_admin.

        :param account: account user is part of
        :param user: the user
        :returns: True if user .reseller_admin, False
                  if user is not a reseller_admin and None if the user
                  doesn't exist.
        """
        req.credentials_valid = True
        user_json = self.get_user_detail(req, account, user)
        if user_json is None:
            req.credentials_valid = False
            return False

        user_detail = json.loads(user_json)

        return '.reseller_admin' in (g['name'] for g in user_detail['groups'])
Returns True if the user is a .reseller_admin.

        :param account: account user is part of
        :param user: the user
        :returns: True if user .reseller_admin, False
                  if user is not a reseller_admin and None if the user
                  doesn't exist.