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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 add_kv_store(self, key, value):
 """Add a key-value store entry. :param key: string :param value: string """

        data = {
            'operation': 'STORE',
            'key': key,
            'value': value
        }
        return self.post(self.make_url("/useragent-kv"), data=to_json(data),
                         headers=self.default_headers).text