def __init__(self, base=None):
        """
        Initialise an instance.

        :param base: The base directory to explore under.
        """
        self.base = os.path.abspath(os.path.normpath(base or os.getcwd()))
        self.prefix = self.base + os.sep
        self.allfiles = None
        self.files = set()

        Initialise an instance.

        :param base: The base directory to explore under.
        
product/gradle-plugin/src/main/python/pip/_vendor/distlib/manifest.py