class MyQueue(object):    def __init__(self, ):        """        Initialize your data structure here.        """        self.instack = []        self.outstack = []    def push(self, x):        """        Push element x to the back of queue.        :type x: int        :rtype: void        """        self.instack.append(x)    def pop(self):        """        Removes the element from in front of queue and returns that element.        :rtype: int        """        if not self.outstack:            if not self.instack:                return            else:                while self.instack:                    node = self.instack.pop()                    self.outstack.append(node)        return self.outstack.pop()    def peek(self):        """        Get the front element.        :rtype: int        """        if not self.outstack:            if not self.instack:                return            else:                while self.instack:                    node = self.instack.pop()                    self.outstack.append(node)        return self.outstack[-1]    def empty(self):        """        Returns whether the queue is empty.        :rtype: bool        """        if len(self.instack) == 0 and len(self.outstack) == 0:            return True        else:            return False# Your MyQueue object will be instantiated and called as such:# obj = MyQueue()# obj.push(x)# param_2 = obj.pop()# param_3 = obj.peek()# param_4 = obj.empty()