count(optional)Captures the number of beats in a measure, that is, the top number of the meter
signature. It must contain a decimal number or an additive expression that evaluates
decimal number, such as 2+3.
Value is plain text.
sym(optional)Indicates the use of a meter symbol instead of a numeric meter signature, that is,
for common time or 'C' with a slash for cut time.
Value conforms to data.METERSIGN.
unit(optional)Contains the number indicating the beat unit, that is, the bottom number of the meter
Value is a decimal number.