def get_category(soup):
    """ Analyze "soup" to extract book's category.

    Args:
      soup -- bs4.BeautifulSoup from http request of book url.
    Return:
        book's category
    """
    breadcrumb = soup.find("ul", {"class": "breadcrumb"})
    items = breadcrumb.find_all("li")
    category = items[2].a.text

    return str(category)