join: join paths parts together to represent a path.

        @return: URI instance of joined path
        @rtype: URI

def join(self, *args):
        """
        join: join paths parts together to represent a path.

        @return: URI instance of joined path
        @rtype: URI
        """
        sep = self.sep
        if sep != '/':
            args = [x.replace(sep, '/') for x in args]
        args = (
            [self.parse_result.path.rstrip('/')] +
            [x.strip('/') for x in args[:-1]] +
            [args[-1]]
            )
        parts = self.parse_result.as_list()
        parts[2] = '/'.join(args)

        result = self.__class__(
            uri_from_parts(parts),
            sep=sep,
            **self._extras()
            )

        result.parse_result.query = self.query.copy()

        return result