code: def get_token(self):
          
          signed_headers = self._get_v4_signed_headers()
          for header in self.HEADERS:
              signed_headers[header] = self.HEADERS[header]
  
          resp = post_with_retry(self.cerberus_url + '/v2/auth/sts-identity', headers=signed_headers)
          throw_if_bad_response(resp)
  
          token = resp.json()['client_token']
          iam_principal_arn = resp.json()['metadata']['aws_iam_principal_arn']
          if self.verbose:
              print('Successfully authenticated with Cerberus as {}'.format(iam_principal_arn), file=sys.stderr)
          logger.info('Successfully authenticated with Cerberus as {}'.format(iam_principal_arn))
  
          return token
docs: Returns a client token from Cerberus