def __init__(self, code, message, uri):
        """
        Initializes a page redirect exception when no location is given.

        @type code: L{bytes}
        @param code: Refers to an HTTP status code, for example
            C{http.NOT_FOUND}. If no C{message} is given, C{code} is mapped to
            a descriptive string that is used instead.

        @type message: L{bytes}
        @param message: A short error message.

        @type uri: L{bytes}
        @param uri: The URI which failed to give a proper location header
            field.
        """
        Error.__init__(self, code, message)
        self.message = self.message + b" to " + uri
        self.uri = uri

        Initializes a page redirect exception when no location is given.

        @type code: L{bytes}
        @param code: Refers to an HTTP status code, for example
            C{http.NOT_FOUND}. If no C{message} is given, C{code} is mapped to
            a descriptive string that is used instead.

        @type message: L{bytes}
        @param message: A short error message.

        @type uri: L{bytes}
        @param uri: The URI which failed to give a proper location header
            field.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/error.py