def update_doc(input, **params):
    """
    Updates document with value from another document
    :param input:
    :param params:
    :return:
    """
    PARAM_SOURCE = 'source'
    SOURCE_COL = 'src.col'
    SOURCE_FIELD = 'src.field'
    PARAM_RESULT = 'result'

    res = input[params.get(PARAM_RESULT)]
    for src in params.get(PARAM_SOURCE):
        res[src[SOURCE_FIELD]] = input[src[SOURCE_COL]][src[SOURCE_FIELD]]
    return res
Updates document with value from another document
    :param input:
    :param params:
    :return: