public boolean removeItem(K key,V item){
  Set<V> values=map.get(key);
  if (values != null)   return values.remove(item);
  return false;
}

public boolean removeItem ( K key , V item ) { Set < V > values = map . get ( key ) ; if ( values != null ) return values . remove ( item ) ; return false ; }
removes the item from the set associated with the given key
