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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def a_urls(html):
    '''
    return normalized urls found in the 'a' tag
    '''
    soup = BeautifulSoup(html, 'lxml')
    for node in soup.find_all('a'):
        try:
            href = node['href']
        except KeyError:
            continue
        yield norm_url(href)