recursive binary search in python

In my previous post, I showed the iterative way to implement binary search algorithm in Python. Here comes the recursive way.

def binary_search_recursive(li, left, right, key):
  while True:
    if left > right:
      return -1
    mid = (left + right) / 2
    if li[mid] == key:
      return mid
    if li[mid] > key:
      right = mid - 1
    else:
      left = mid + 1
    return binary_search_recursive(li, left, right, key)

if __name__ == "__main__":
  li = [1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12]
  left = 0
  right = len(li)
  for key in  [8, 6, 1, 12, 7]:
    index = binary_search_recursive(li, left, right, key)
    print key, index