--- Disconnect from a signal.
-- @tparam string name The name of the signal.
-- @tparam function func The callback that should be disconnected.
-- @method disconnect_signal

--- Emit a signal.
--
-- @tparam string name The name of the signal.
-- @param ... Extra arguments for the callback functions. Each connected
--   function receives the object as first argument and then any extra
--   arguments that are given to emit_signal().
-- @method emit_signal

--- Connect to a signal.
-- @tparam string name The name of the signal.
-- @tparam function func The callback to call when the signal is emitted.
-- @method connect_signal

--- Connect to a signal weakly.
--
-- This allows the callback function to be garbage collected and
-- automatically disconnects the signal when that happens.
--
-- **Warning:**
-- Only use this function if you really, really, really know what you
-- are doing.
-- @tparam string name The name of the signal.
-- @tparam function func The callback to call when the signal is emitted.
-- @method weak_connect_signal