def __init__(self, archivePathname):
        """
        Create a ZipArchive, treating the archive at archivePathname as a zip
        file.

        @param archivePathname: a L{bytes} or L{unicode}, naming a path in the
            filesystem.
        """
        self.path = archivePathname
        self.zipfile = ZipFile(_coerceToFilesystemEncoding('',
                                                           archivePathname))
        self.pathInArchive = _coerceToFilesystemEncoding(archivePathname, '')
        # zipfile is already wasting O(N) memory on cached ZipInfo instances,
        # so there's no sense in trying to do this lazily or intelligently
        self.childmap = {}      # map parent: list of children

        for name in self.zipfile.namelist():
            name = _coerceToFilesystemEncoding(self.path, name).split(self.sep)
            for x in range(len(name)):
                child = name[-x]
                parent = self.sep.join(name[:-x])
                if parent not in self.childmap:
                    self.childmap[parent] = {}
                self.childmap[parent][child] = 1
            parent = _coerceToFilesystemEncoding(archivePathname, '')

        Create a ZipArchive, treating the archive at archivePathname as a zip
        file.

        @param archivePathname: a L{bytes} or L{unicode}, naming a path in the
            filesystem.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/zippath.py