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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 get_subdomain(url):
 """ Determines the domain's subdomains. :param str url: the url to extract any subdomains from :return str: subdomains of url """

        allowed_domain = UrlExtractor.get_allowed_domain(url)
        return allowed_domain[:len(allowed_domain) - len(
            UrlExtractor.get_allowed_domain(url, False))]