XkbLookupKeySym is the equivalent of the core
XLookupKeySym function. For the core keyboard, given a keycode
key and an Xkb state
state, XkbLookupKeySym returns the symbol associated with the key in
sym_rtrn and the list of modifiers that should still be applied in
mods_rtrn. The
state parameter is the state from a KeyPress or KeyRelease event.
XkbLookupKeySym returns True if it succeeds.