Re-emit signal a received signal

Hi,

I'd like that when a widget receives a signal, it emits another signal
with the same data to another widget.
Let's say I have the following hierarchy:
  window -> box -> button
I put an event handler on the button and I'd like that when the box
receives a key_press signal, it gets forwarded to the button and (of
course my actual problem is more complicated than two widgets).

I found GtkSignal.emit but I don't know how to use it with type
Gdk.event. I tried to send the signal data with `CAML (Obj.repr
gdk_keysym) but that doesn't work (it's not compatible with what
g_value_set_variant() accepts).

Is this doable?
Also, is there any rule or documentation about the data_set type in Gobject?

Thanks.

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Adrien Nader