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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 pipe_xpathfetchpage(context=None, _INPUT=None, conf=None, **kwargs):
 """A source that fetches the content of a given website as DOM nodes or a string. Loopable. context : pipe2py.Context object _INPUT : pipeforever pipe or an iterable of items or fields conf : dict URL -- url object contain the URL to download xpath -- xpath to extract html5 -- use html5 parser? useAsString -- emit items as string? TODOS: - don't retrieve pages larger than 1.5MB - don't retrieve if page is not indexable. Yields ------ _OUTPUT : items """

    conf = DotDict(conf)
    urls = utils.listize(conf['URL'])

    for item in _INPUT:
        for item_url in urls:
            url = utils.get_value(DotDict(item_url), DotDict(item), **kwargs)
            url = utils.get_abspath(url)
            f = urlopen(url)

            # TODO: it seems that Yahoo! converts relative links to
            # absolute. This needs to be done on the content but seems to
            # be a non-trival task python?
            content = unicode(f.read(), 'utf-8')

            if context and context.verbose:
                print '............Content .................'
                print content
                print '...............EOF...................'

            xpath = conf.get('xpath', **kwargs)
            html5 = conf.get('html5', **kwargs) == 'true'
            use_as_string = conf.get('useAsString', **kwargs) == 'true'
            tree = html5parser.parse(f) if html5 else html.parse(f)
            root = tree.getroot()
            items = root.xpath(xpath)

            if context and context.verbose:
                print 'XPathFetchPage: found count items:', len(items)

            for etree in items:
                i = utils.etree_to_dict(etree)

                if context and context.verbose:
                    print '--------------item data --------------------'
                    print i
                    print '--------------EOF item data ----------------'

                if use_as_string:
                    yield {'content': unicode(i)}
                else:
                    yield i

        if item.get('forever'):
            # _INPUT is pipeforever and not a loop,
            # so we just yield our item once
            break