func (us *unsafeSet) Copy() Set {
	cp := NewUnsafeSet()
	for val := range us.d {
		cp.Add(val)
	}

	return cp
}
func (us *unsafeSet) Copy() Set {
	cp := NewUnsafeSet()
	for val := range us.d {
		cp.Add(val)
	}

	return cp
}
func ( us * unsafeSet ) Copy ( ) Set { cp := NewUnsafeSet ( ) for val := range us . d { cp . Add ( val ) } return cp }
// Copy creates a new Set containing the values of the first
Copy creates a new Set containing the values of the first