def extract_summs_from_src(src, tags, empty_placeholder="."):
    """Returns 3 summaries based on passed tags. By convention, verdicts, pros,
    and cons are tagged as 1, 2, 3, respectively.

    Args:
        src (list): src documents
        tags (list): integer tags
        empty_placeholder: symbol to use if a summary is missing
    """
    assert len(src) == len(tags)
    verd = []
    pros = []
    cons = []
    for indx, t in enumerate(tags):
        if t == 1:
            verd.append(src[indx])
        if t == 2:
            pros.append(src[indx])
        if t == 3:
            cons.append(src[indx])
    verd = " ".join(verd) if verd else empty_placeholder
    pros = " ".join(pros) if pros else empty_placeholder
    cons = " ".join(cons) if cons else empty_placeholder
    return verd, pros, cons