python 데이터 구조의 대기 열 실현

#!/usr/bin/env python
#coding:utf-8

queue = []       //             ,       

def push():     //        
    value = raw_input('       : ') 
    queue.append(value)
    choose()

def pop():      //    
    if len(queue) == 0:     
        print "     " 
    else:
        queue.pop(0)
    choose() 

def view():     //        
    print queue 
    choose()

def showmenu():     //        
    print '''  
    u(push):    
    o(pop):    
    v(view):      
    q(quit):   
    ''' 
    choose()

def choose():       //      
    choice = raw_input('       : ').lower()
    if choice == 'u':
        push()
    elif choice == 'o':
        pop()    
    elif choice == 'v':
        view()
    elif choice == 'q':
        print '——     ——'
        exit()   
    else:
        print '            '
        showmenu()

showmenu()