code: func IgnoreExpired(err error) error {
  	vErr, ok := err.(*jwt.ValidationError)
  	if ok && vErr.Errors == jwt.ValidationErrorExpired {
  		return nil
  	}
  	return err
  }
docs: // IgnoreExpired checks if the input error is only an expired error. Nil is returned in
  // this case, else the original error