+ (tempo-unit ,ly:duration? "The unit for the metronome count.")
+ (tonic ,ly:pitch? "Base of the scale")
+ (tremolo-type ,integer? "speed of tremolo, e.g. 16 for c4:16")
+ (trill-pitch ,ly:pitch? "Pitch of other note of the trill.")
+ (type ,symbol? "The type of this music object. Determines iteration in some cases.")
+ (types ,list? "The types of this music object; determines by what
+engraver this music expression is processed.")
+ (tweaks ,list? "An alist of properties to override in the backend
+-for the grob made of this event.")