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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 parse_tag (self, tag, attr, value, name, base):
 """Add given url data to url list."""

        assert isinstance(tag, unicode), repr(tag)
        assert isinstance(attr, unicode), repr(attr)
        assert isinstance(name, unicode), repr(name)
        assert isinstance(base, unicode), repr(base)
        assert isinstance(value, unicode) or value is None, repr(value)
        # look for meta refresh
        if tag == u'meta' and value:
            mo = refresh_re.match(value)
            if mo:
                self.found_url(mo.group("url"), name, base)
            elif attr != 'content':
                self.found_url(value, name, base)
        elif attr == u'style' and value:
            for mo in css_url_re.finditer(value):
                url = unquote(mo.group("url"), matching=True)
                self.found_url(url, name, base)
        elif attr == u'archive':
            for url in value.split(u','):
                self.found_url(url, name, base)
        elif attr == u'srcset':
            for img_candidate in value.split(u','):
                url = img_candidate.split()[0]
                self.found_url(url, name, base)
        else:
            self.found_url(value, name, base)