settings.py 文件源码

def __init__(self, setting, link, pattern):
        self.setting = setting
        self.link = link.upper()
        self.pattern = pattern

        # Determine the settings that need to be present
        formatter = string.Formatter()
        self.placeholders = [field
                             for _, field, _, _ in formatter.parse(pattern)
                             if field is not None]