| ### Instruction: | |
| Give me a working Python function for binary_search. | |
| ### Answer: | |
| ```python | |
| def binary_search(items, target): | |
| low = 0 | |
| high = len(items) - 1 | |
| while low <= high: | |
| mid = (low + high) // 2 | |
| value = items[mid] | |
| if value == target: | |
| return mid | |
| if value < target: | |
| low = mid + 1 | |
| else: | |
| high = mid - 1 | |
| return -1 | |
| ``` | |
| ### Instruction: |