def get_upc(book_detail_soup):
    """ Get the book's upc from the book detail soup """
    upc = ''
    book_table = book_detail_soup.find('table', { 'class' : 'table table-striped' })
    trs = book_table.find_all('tr')
    #return trs
    for tr in trs:
        if tr.find('th').get_text(strip=True) == 'UPC':
            upc = tr.find('td').get_text(strip=True)
    return upc