def process_row(row_tag):
    """
    return row_tag as a list of HTML-tag-stripped strings

    row_tag: a <tr> bs4 Tag, where each column contains exactly one string
    """
    res = []
    for tag in row_tag.children:
        if not tag.string or tag.string.isspace():
            res.append(None)
        else:
            res.append(tag.string)
    return res
