base.py 文件源码

def evaluate(self, expression) -> object:
        if not isinstance(expression, collections.abc.Mapping):
            return expression
        try:
            import_path = expression['class']
        except KeyError:
            return expression
        f = self.import_(import_path)
        args = expression.get('*', ())
        if isinstance(args, str) or \
           not isinstance(args, collections.abc.Sequence):
            raise ConfigValueError(
                '"*" field must be a list, not ' + repr(args)
            )
        kw = {k: v for k, v in expression.items() if k not in ('class', '*')}
        if self.recurse:
            args = map(self.evaluate, args)
            kw = {k: self.evaluate(v) for k, v in kw.items()}
        return f(*args, **kw)