func (s *Int32) Remove(num int32) bool {
	_, ok := s.nodeMap[num]
	if ok {
		delete(s.nodeMap, num)
	}
	return ok
}
Remove an item
package set
type Int32 struct {
	nodeMap map[int32]struct{}
}
func NewInt32(nums []int32) *Int32 {
	s := &Int32{}
	for _, num := range nums {
		s.Add(num)
	}
	return s
}
func (s *Int32) Add(num int32) *Int32 {
	if s.nodeMap == nil {
		s.nodeMap = make(map[int32]struct{})
	}
	_, ok := s.nodeMap[num]
	if !ok {
		s.nodeMap[num] = struct{}{}
	}
	return s
}
func (s *Int32) Clear() {
	s.nodeMap = make(map[int32]struct{})
}