code: def user_invite(self, username, email, roles):
          
  
          uri = 'openstack/users'
          data = {
              "username": username,
              "email": email,
              "roles": list(set(roles))
          }
          post_body = json.dumps(data)
          resp, body = self.post(uri, body=post_body)
          self.expected_success(200, resp.status)
          body = json.loads(body)
          return rest_client.ResponseBody(resp, body)
docs: Invite a user to the tenant.