def __new__(cls, pack_uri_str):
        if not pack_uri_str[0] == '/':
            tmpl = "PackURI must begin with slash, got '%s'"
            raise ValueError(tmpl % pack_uri_str)
        return str.__new__(cls, pack_uri_str)
dataset/ETHPy150Open python-openxml/python-docx/docx/opc/packuri.py/PackURI.__new__/original