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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 acceptmergerequest(self, project_id, mergerequest_id, merge_commit_message=None):
 """ Update an existing merge request. :param project_id: ID of the project originating the merge request :param mergerequest_id: ID of the merge request to accept :param merge_commit_message: Custom merge commit message :return: dict of the modified merge request """


        data = {'merge_commit_message': merge_commit_message}

        request = requests.put(
            '{0}/{1}/merge_request/{2}/merge'.format(self.projects_url, project_id, mergerequest_id),
            data=data, headers=self.headers, verify=self.verify_ssl, auth=self.auth, timeout=self.timeout)

        if request.status_code == 200:
            return request.json()
        else:
            return False