pyton datastruct

BaseConvension.py

Class Stack:
    def __init__(self):
       self.items = []
    def isEmpty(self):
       return self.items == []
    def push(self,item):
      self.items.append(item)
    def pop(self.item):
       return self.items.pop()
    def peek(self):
       return self.items[len(self.items)-1]
    def size(self):
      return len(self.items)
def conventer(number,base):
    digits = "0123456789ABCDEF"
    k=Stack()
    while number>0:
      n=number%base
      k.push(n)
      number = number%base
   string=""
   while not k.isEmpty():
       string = string + digits[k.pop()]
  return string