code: def updateEnterpriseUser(self, username, idpUsername):
          
          params = {
              "f" : "json",
              "username" : username,
              "idpUsername" : idpUsername
          }
          url = self._url + "/users/updateEnterpriseUser"
          return self._post(url=url,
                            param_dict=params,
                            proxy_url=self._proxy_url,
                            proxy_port=self._proxy_port)
docs: This operation allows an administrator to update the idpUsername
          for an enterprise user in the portal. This is used when migrating
          from accounts used with web-tier authentication to SAML
          authentication.
  
          Parameters:
             username - username of the enterprise account
             idpUsername - username used by the SAML identity provider