code: def _get_registry_auth(registry_url, config_path):
          
          username = None
          password = None
          try:
              docker_config = json.load(open(config_path))
          except ValueError:
              # The configuration file is empty
              return username, password
          if docker_config.get('auths'):
              docker_config = docker_config['auths']
          auth_key = docker_config.get(registry_url, {}).get('auth', None)
          if auth_key:
              username, password = base64.b64decode(auth_key).split(':', 1)
          return username, password
docs: Retrieve from the config file the current authentication for a given URL, and
          return the username, password