Python Contact Book Application

I need a small, self-contained contact book written in Python. The program must let me add new contacts, remove existing ones, and quickly search or filter through the list. All data has to persist in a single local file—CSV, JSON, or a simple text format is fine as long as it’s human-readable and easy to back up.

Core requirements
• Clean, well-commented Python 3 code with clear functions for each action (add, delete, search/filter).
• A simple menu-driven or command-line interface so I can use it without diving into the code.
• Efficient search that works on name and any other fields you include.
• Graceful handling of duplicate or missing entries.

Deliverables
1. The complete .py file(s).
2. The sample data file pre-populated with a few entries so I can test right away.
3. A short README explaining setup, usage, and how to change the storage file path if I ever need to.

If you can keep external dependencies to the standard library, that would be ideal.