def update_summary(summary: dict, result: dict) -> dict:
    """
    Append values from result to summary.

    :param summary: summary dict (with aggregated results)
    :param result: result dict (with partial results)
    :return: the updated summary dict
    >>> a = {'a': 1, 'b': 2}
    >>> b = {'a': [3]}
    >>> c = update_summary(summary=b, result=a)
    >>> assert c['a'] == [3, 1]
    """
    for key, value in summary.items():
        if key in result.keys():
            new_value = result[key]
            summary[key].append(new_value)
    return summary