Build a Key-Value StoreStep 2 of 5

Overwrite and List Keys

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Step 2 — Overwrite and List Keys

Now extend the store with two more methods:

  • keys() — return a list of all keys
  • exists(key) — return True if the key exists

Also confirm that put on an existing key overwrites the value, not adds a duplicate.

Hints
Starter code
class KeyValueStore:
    def __init__(self):
        self._store = {}

    def put(self, key, value):
        self._store[key] = value

    def get(self, key):
        return self._store.get(key)

    def delete(self, key):
        if key in self._store:
            del self._store[key]
            return True
        return False

    def size(self):
        return len(self._store)

    def keys(self):
        """Return a list of all keys."""
        # TODO: Implement this
        pass

    def exists(self, key):
        """Return True if key exists, False otherwise."""
        # TODO: Implement this
        pass
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