How to Set Nested Dict Value Creating Missing Keys in Python

def set_nested_value(d, keys, value):
    """
    Set a value in a nested dict, creating missing intermediate keys.
    
    Args:
        d: The dict to modify
        keys: Iterable of keys forming the path (e.g., ['a', 'b', 'c'])
        value: The value to set at the final key
    """
    current = d
    for key in keys[:-1]:
        # Create intermediate dict if key doesn't exist or isn't a dict
        if key not in current or not isinstance(current[key], dict):
            current[key] = {}
        current = current[key]
    current[keys[-1]] = value


if __name__ == "__main__":
    # Example usage
    data = {}
    set_nested_value(data, ['users', 'alice', 'age'], 30)
    set_nested_value(data, ['users', 'alice', 'email'], 'alice@example.com')
    set_nested_value(data, ['users', 'bob', 'age'], 25)
    set_nested_value(data, ['settings', 'theme', 'dark'], True)
    
    # Add nested value with existing dict preserved
    set_nested_value(data, ['users', 'alice', 'prefs', 'language'], 'en')
    
    print(data)
    # Expected: {'users': {'alice': {'age': 30, 'email': 'alice@example.com', 'prefs': {'language': 'en'}}, 'bob': {'age': 25}}, 'settings': {'theme': {'dark': True}}}