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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 extract_upgrade_scripts(self):
 """ Extract the OpenQuake upgrade scripts from the links in the GitHub page """

        link_pattern = '>\s*{0}\s*<'.format(self.pattern[1:-1])
        page = urllib.request.urlopen(self.upgrades_url).read()
        for mo in re.finditer(link_pattern, page):
            scriptname = mo.group(0)[1:-1].strip()
            yield self.parse_script_name(scriptname)