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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 remove_api_key(self):
 """ Removes the user's existing API key, if present, and sets the current instance's 'api_key' attribute to the empty string. Returns: `NoneType`: None. """

        url = self.record_url + "/remove_api_key"
        res = requests.patch(url=url, headers=HEADERS, verify=False)
        res.raise_for_status()
        self.api_key = ""