def update_dictionary(default, updates):
    """
    Updates default dictionary with elements from
    optional dictionary.

    @param default: A python dictionary containing the minimal
    required arguments to create a CLI object.
    @param updates: A python dictionary containing attributes
    to overwrite on default dictionary.

    @return default: The modified default python dictionary.
    """
    if updates:
        for key in set(default.keys()).intersection(set(updates.keys())):
            default[key] = updates[key]
    return default
