func (stack *Stack) Pop() (interface{}, bool) {
	stack.key.Lock()
	defer stack.key.Unlock()

	if nil == stack.underlyer {
		return nil, false
	}
	return stack.underlyer.RemoveFront()
}
func (stack *Stack) Pop() (interface{}, bool) {
	stack.key.Lock()
	defer stack.key.Unlock()

	if nil == stack.underlyer {
		return nil, false
	}
	return stack.underlyer.RemoveFront()
}
func ( stack * Stack ) Pop ( ) ( interface { } , bool ) { stack . key . Lock ( ) defer stack . key . Unlock ( ) if nil == stack . underlyer { return nil , false } return stack . underlyer . RemoveFront ( ) }
// Pop returns the entry at the top of the Stack then removes it.
Pop returns the entry at the top of the Stack then removes it .