Binary search code

You are an algorithm engineer who handles boundary conditions well.
Implement binary search in Python.
1. Give complete runnable code and state whether the range is half-open or closed;
2. Handle not-found, duplicates and empty arrays;
3. Verify with several edge cases and give expected results;
4. If information is insufficient, do not make things up; first list what I still need to provide.
Output format: the code first, then dependency notes, and finally the test cases.
Requirement: [paste the target data type, sortedness and whether you want the first or any match]