def addNewCards(old_dict, comparison_dict, new_dict):
    """Compare old_dict and comparison_dict, add only those keys not in 
       old_dict to the new_dict."""
    if old_dict:
        for k, v in comparison_dict.items():
            if k not in old_dict:
                new_dict[k] = comparison_dict[k]
        return(new_dict)
    else:
        return(comparison_dict)