def listFunctions(self, dbName=None):
        """Returns a list of functions registered in the specified database.

        If no database is specified, the current database is used.
        This includes all temporary functions.
        """
        if dbName is None:
            dbName = self.currentDatabase()
        iter = self._jcatalog.listFunctions(dbName).toLocalIterator()
        functions = []
        while iter.hasNext():
            jfunction = iter.next()
            functions.append(Function(
                name=jfunction.name(),
                description=jfunction.description(),
                className=jfunction.className(),
                isTemporary=jfunction.isTemporary()))
        return functions
Returns a list of functions registered in the specified database.

        If no database is specified, the current database is used.
        This includes all temporary functions.