Casts a from the spellbook. Only protected (i.e. usable only by the Blizzard UI) if the given
id corresponds to a spell which can be cast (not a passive spell) and is not a trade skill; can be used by addons to cast the "spells" that open trade skill windows.
See also Spell functions.
id- Index of a spell in the spellbook (
bookType- Type of spellbook (
pet- The pet's spellbook
spell- The player's spellbook