code: def _AddCredentialConfiguration(
        self, path_spec, credential_type, credential_data):
      
      credential_configuration = configurations.CredentialConfiguration(
          credential_data=credential_data, credential_type=credential_type,
          path_spec=path_spec)
  
      self._credential_configurations.append(credential_configuration)
docs: Adds a credential configuration.
  
      Args:
        path_spec (dfvfs.PathSpec): path specification.
        credential_type (str): credential type.
        credential_data (bytes): credential data.