src/main/java/seedu/planner/model/ModelManager.java
private void removeDayMapping(Activity act, Day day) {
        if (activityDayMap.containsKey(act)) {
            activityDayMap.get(act).remove(day);
        }
    }
/**
     * Removes the mapping of an {@code Activity} in the {@code Day} related {@code HashMap} when an activity is
     * undscheduled.
     */
Removes the mapping of an  Activity in the  Day related  HashMap when an activity is
undscheduled.
Removes the mapping of an Activity in the Day related HashMap when an activity is undscheduled .
private void removeDayMapping(Activity act, Day day) {
        if (activityDayMap.containsKey(act)) {
            activityDayMap.get(act).remove(day);
        }
    }
private void removeDayMapping ( Activity act , Day day ) { if ( activityDayMap . containsKey ( act ) ) { activityDayMap . get ( act ) . remove ( day ) ; } }
Removes the mapping of an {@code Activity} in the {@code Day} related {@code HashMap} when an activity is
 undscheduled.
Removes the mapping of an { @code Activity } in the { @code Day } related { @code HashMap } when an activity is undscheduled .