def register_identifier(data_format, data_class, identifier, force=False):
 if ((not ((data_format, data_class) in _identifiers)) or force):
  _identifiers[(data_format, data_class)] = identifier
 else:
  raise IORegistryError(u"Identifier for format '{0}' and class '{1}' is already defined".format(data_format, data_class.__name__))

def register_identifier ( data_format , data_class , identifier , force = False ) : if ( ( not ( ( data_format , data_class ) in _identifiers ) ) or force ) : _identifiers [ ( data_format , data_class ) ] = identifier else : raise IORegistryError ( u"Identifier for format '{0}' and class '{1}' is already defined" . format ( data_format , data_class . __name__ ) )
associate an identifier function with a specific data type .