code: func BadSignatureAlgorithm(detail string, a ...interface{}) *ProblemDetails {
  	return &ProblemDetails{
  		Type:       BadSignatureAlgorithmProblem,
  		Detail:     fmt.Sprintf(detail, a...),
  		HTTPStatus: http.StatusBadRequest,
  	}
  }
docs: // BadSignatureAlgorithm returns a ProblemDetails with a BadSignatureAlgorithmProblem
  // and a 400 Bad Request status code.