docs: def get_url(url_base, tenant_id, user, password, type, region):
      """It get the url for a concrete service
      :param url_base: keystone url
      :param tenand_id: the id of the tenant
      :param user: the user
      :param paassword: the password
      :param type: the type of service
      :param region: the region
      """
      url = 'http://' + url_base + '/v2.0/tokens'
      headers = {'Accept': 'application/json'}
      payload = {'auth': {'tenantName': '' + tenant_id + '',
                          'passwordCredentials':
                          {'username': '' + user + '',
                          'password': '' + password + ''}}}
      try:
          response = requests.post(url, headers=headers,
                                   data=json.dumps(payload))
          response_json = response.json()
          services = response_json['access']['serviceCatalog']
      except Exception as e:
          raise Exception('Error to obtain a image ' + e.message)
  
      for service in services:
          if service['type'] == type and service['region'] == region:
              for endpoint in service['endpoints']:
                  return endpoint['publicURL']