def get_feature(tablerow):
    """Extract the feature of a tablerow.

    Parameters:
        tablerow (bs4.BeautifulSoup): A tablerow from the wikipedia infobox in html

    Returns:
        feature (str): Feature of the tablerow

    Raises:
        None
    """
    tableheader = tablerow.find('th')
    if tableheader:
        feature = tableheader.text
    else:
        feature = ''
    return feature