python 判断两个列表是否有公共元素

def common_data(list1, list2):  
     result = False  
     for x in list1:  
         for y in list2:  
             if x == y:  
                 result = True  
     return result  
print(common_data([1,2,3,4,5], [5,6,7,8,9]))  
print(common_data([1,2,3,4,5], [6,7,8,9]))