Casts a spell specified by id (optionally on a specified unit). Only protected (i.e. usable only by the Blizzard UI) if the given spell is castable (not passive) and is not a trade skill; can be used by addons to cast the "spells" that open trade skill windows.
See also Spell functions.
spellID- ID of the spell to cast (
target- A unit to target with the spell (