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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 keys(cls, fqdn, sort_by=None):
 """Display keys information about a domain."""

        meta = cls.get_fqdn_info(fqdn)
        url = meta['domain_keys_href']
        return cls.json_get(cls.get_sort_url(url, sort_by))