def __init__(self, template, handler=None, name=None, build_only=False):
        """Initializes this route.

        :param template:
            A regex to be matched.
        :param handler:
            A callable or string in dotted notation to be lazily imported,
            e.g., ``'my.module.MyHandler'`` or ``'my.module.my_function'``.
        :param name:
            The name of this route, used to build URIs based on it.
        :param build_only:
            If True, this route never matches and is used only to build URIs.
        """
        if build_only and name is None:
            raise ValueError(
                self % "Route %r is build_only but doesn't have a name.")

        self.template = template
        self.handler = handler
        self.name = name
        self.build_only = build_only
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/webapp2-2.5.1/webapp2.py/BaseRoute.__init__/swapped operands of `%`