def get_default(key, ctx):
    """
    Get the default argument using a user instance property
    :param value: The name of the property to use
    :param ctx: The click context (which will be used to get the user)
    :return: The default value, or None
    """
    try:
        value = getattr(ctx.code_builder, key)
        if value == '':
            value = None
    except KeyError:
        value = None
    return value
