message: Make the private function validateIntermediateSigningKey return void. The return value is always unused.
diff: @@ -561,7 +561,7 @@ public final class PaymentMethodTokenRecipient {
  return Collections.singletonList(provider);
  }
  - private JsonObject validateIntermediateSigningKey(final JsonObject intermediateSigningKey)
  + private void validateIntermediateSigningKey(final JsonObject intermediateSigningKey)
  throws GeneralSecurityException {
  if (!intermediateSigningKey.has(PaymentMethodTokenConstants.JSON_SIGNATURES_KEY)
  || !intermediateSigningKey.has(PaymentMethodTokenConstants.JSON_SIGNED_KEY_KEY)
  @@ -569,7 +569,6 @@ public final class PaymentMethodTokenRecipient {
  throw new GeneralSecurityException(
  "intermediateSigningKey must contain exactly signedKey and signatures");
  }
  - return intermediateSigningKey;
  }
  private void validateSignedKey(final JsonObject signedKey) throws GeneralSecurityException {
  