def add_missed_dis(doc, dis_dict, dis_to_add):
    """Add missed diseases through manual lookup

    Args:
        doc (Doc): nlp on text
        dis_dict (dict): Existing frequency dict of diseases
        dis_to_add (set): New diseases to add if found in doc

    Returns:
        dict: Modified dis_dict
    """
    dis_dict2 = {}
    for tok in doc:
        tok_upper = tok.text.upper()
        if tok_upper in dis_to_add:
            dis_dict2[tok_upper] = dis_dict2.get(tok_upper, 0) + 1


    for dis, freq in dis_dict2.items():
        if dis not in dis_dict:
            dis_dict[dis] = freq

    return dis_dict