python queue structure

#!/ur/bin/env python
__author__ = "lynn lin"
__lience__ = "MIT"

class queue(object):
        def __init__(self):
                self.que = []
        
        def __len__(self):
                return len(self.que)

        def QueueEmpty(self):
            return self.__len__()

        def EnQueue(self,value):
                self.que.insert(0,value)

        def DeQueue(self):
            try:
                    return self.que.pop()
            except:
                raise UnderFlowError,"queue is empty,no value to pop"
        
        def has_key(self,value):
            if value in self.que:
                return True
            else:
                return False