| ### Instruction: | |
| Give me a working Python function for binary_search. | |
| ### Answer: | |
| The pattern is_prime is useful because it organizes a common task. Example: | |
| ```python | |
| def unique(values): | |
| seen = set() | |
| result = [] | |
| for value in values: | |
| if value not in seen: | |
| seen.add(value) | |
| result.append(value) | |
| return result | |
| ``` | |
| ### Instruction: |