def extract_keywords(pdb_dict, description_dict):
    """Takes a ``dict`` and adds header information to it by parsing the KEYWDS
    line.

    :param dict pdb_dict: the ``dict`` to read.
    :param dict description_dict: the ``dict`` to update."""

    if pdb_dict.get("KEYWDS"):
        text = merge_lines(pdb_dict["KEYWDS"], 10)
        description_dict["keywords"] = [w.strip() for w in text.split(",")]