Jose\Signer::createSigner PHP Method

    public static function createSigner(array $signature_algorithms)
    {
        $signer = new self($signature_algorithms);
        return $signer;
    }

 /**
  * @param mixed                     $payload
  * @param \Jose\Object\JWKInterface $signature_key
  * @param array                     $protected_headers
  *
  * @return \Jose\Object\JWSInterface
  */
 private static function createJWSWithDetachedPayloadAndSign($payload, JWKInterface $signature_key, array $protected_headers = [], $headers = [])
 {
     $jws = self::createJWS($payload, true);
     $jws = $jws->addSignatureInformation($signature_key, $protected_headers, $headers);
     $complete_headers = array_merge($protected_headers, $headers);
     Assertion::keyExists($complete_headers, 'alg', 'No "alg" parameter set in the header');
     $signer = Signer::createSigner([$complete_headers['alg']]);
     $signer->sign($jws);
     return $jws;
 }