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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 _make_signing_request(self, message):
 """Makes a request to the API signBlob API."""

        message = _helpers.to_bytes(message)

        method = 'POST'
        url = _SIGN_BLOB_URI.format(self._service_account_email)
        headers = {}
        body = json.dumps({
            'bytesToSign': base64.b64encode(message).decode('utf-8'),
        })

        self._credentials.before_request(self._request, method, url, headers)
        response = self._request(
            url=url, method=method, body=body, headers=headers)

        if response.status != http_client.OK:
            raise exceptions.TransportError(
                'Error calling the IAM signBytes API: {}'.format(
                    response.data))

        return json.loads(response.data.decode('utf-8'))