How to Build an In-Memory CRUD Repository Class in Python

class Repository:
    def __init__(self):
        self._data = {}

    def create(self, key, value):
        self._data[key] = value
        return key

    def read(self, key):
        return self._data.get(key)

    def update(self, key, value):
        if key not in self._data:
            raise KeyError(f"Key '{key}' not found")
        self._data[key] = value
        return value

    def delete(self, key):
        if key not in self._data:
            raise KeyError(f"Key '{key}' not found")
        return self._data.pop(key)

    def list_all(self):
        return list(self._data.items())


if __name__ == "__main__":
    repo = Repository()

    repo.create("user1", {"name": "Alice", "age": 30})
    repo.create("user2", {"name": "Bob", "age": 25})

    print(f"Initial: {repo.list_all()}")
    print(f"Read user1: {repo.read('user1')}")
    
    repo.update("user2", {"name": "Robert", "age": 26})
    print(f"After update: {repo.list_all()}")
    
    repo.delete("user1")
    print(f"After delete: {repo.list_all()}")