def extends(dictionnary, **kwargs):
    """
    For each kwarg, will check if the key already exist in var,
    create it and set the given value if not.
    dictionnary is expected to be a dict
    Returns the extended dictionnary.
    """
    for k, v in kwargs.items():
        if not k in dictionnary:
            dictionnary[k] = v
    return dictionnary