How to use the aioftp.server.PathPermissions function in aioftp

    @PathPermissions(PathPermissions.writable)
    async def rnto(self, connection, rest):
        real_path, virtual_path = self.get_paths(connection, rest)
        rename_from = connection.rename_from
        del connection.rename_from
        await connection.path_io.rename(rename_from, real_path)
        connection.response("250", "")
        return True

    @PathPermissions(PathPermissions.writable)
    async def rmd(self, connection, rest):
        real_path, virtual_path = self.get_paths(connection, rest)
        await connection.path_io.rmdir(real_path)
        connection.response("250", "")
        return True

    @PathPermissions(PathPermissions.readable)
    async def mlst(self, connection, rest):
        real_path, virtual_path = self.get_paths(connection, rest)
        s = await self.build_mlsx_string(connection, real_path)
        connection.response("250", ["start", s, "end"], True)
        return True

    @PathPermissions(PathPermissions.writable)
    async def dele(self, connection, rest):
        real_path, virtual_path = self.get_paths(connection, rest)
        await connection.path_io.unlink(real_path)
        connection.response("250", "")
        return True

    @PathPermissions(PathPermissions.readable)
    async def retr(self, connection, rest):

        @ConnectionConditions(
            ConnectionConditions.data_connection_made,
            wait=True,
            fail_code="425",
            fail_info="Can't open data connection")
        @worker
        async def retr_worker(self, connection, rest):
            stream = connection.data_connection
            del connection.data_connection
            file_in = connection.path_io.open(real_path, mode="rb")
            async with file_in, stream:
                if connection.restart_offset:
                    await file_in.seek(connection.restart_offset)
                async for data in file_in.iter_by_block(connection.block_size):