def child(self, path):
        """
        Return a new ZipPath representing a path in C{self.archive} which is
        a child of this path.

        @note: Requesting the C{".."} (or other special name) child will not
            cause L{InsecurePath} to be raised since these names do not have
            any special meaning inside a zip archive.  Be particularly
            careful with the C{path} attribute (if you absolutely must use
            it) as this means it may include special names with special
            meaning outside of the context of a zip archive.
        """
        joiner = _coerceToFilesystemEncoding(path, ZIP_PATH_SEP)
        pathInArchive = _coerceToFilesystemEncoding(path, self.pathInArchive)
        return ZipPath(self.archive, joiner.join([pathInArchive, path]))

        Return a new ZipPath representing a path in C{self.archive} which is
        a child of this path.

        @note: Requesting the C{".."} (or other special name) child will not
            cause L{InsecurePath} to be raised since these names do not have
            any special meaning inside a zip archive.  Be particularly
            careful with the C{path} attribute (if you absolutely must use
            it) as this means it may include special names with special
            meaning outside of the context of a zip archive.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/zippath.py