Moment when() { return when_; }
Score_column(Moment when);
static int compare(Score_column & c1, Score_column &c2);
void add_duration(Moment );
void preprocess();
Moment when() { return when_; }
Score_column(Moment when);
static int compare(Score_column & c1, Score_column &c2);
void add_duration(Moment );
void preprocess();