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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 check_link(self, link):
 """ Check if a link has been already converted. """

        r = requests.get(CHECK_LINK_ENDPOINT + link)
        if r.status_code != 200:
            raise GfycatClientError('Unable to check the link',
                                    r.status_code)

        return r.json()