code: def link_user_account(self, user_id, body):
          
          url = self._url('{}/identities'.format(user_id))
          return self.client.post(url, data=body)
docs: Link user accounts.
  
          Links the account specified in the body (secondary account) to the
          account specified by the id param of the URL (primary account).
  
          Args:
              id (str): The user_id of the primary identity where you are linking
                  the secondary account to.
  
              body (dict): Please see: https://auth0.com/docs/api/v2#!/Users/post_identities