def add_feature(input_dict):
    """
    Add a feature to Annotated Document Corpus.

    :param adc: Annotated Document Corpus
    :param feature_name: the name of new feature
    :param feature_values: list of features values
    :param feature_value_prefix:  prefix to feature value

    :return: new adc
    """

    for i, document in enumerate(input_dict["adc"].documents):
        document.features[input_dict["feature_name"]] = input_dict["feature_value_prefix"] + str(input_dict["feature_values"][i])
    return {"adc":input_dict["adc"]}