code: func (p *Signing) SetClientCertKeyPairFromFile(certFile string, keyFile string) error {
  	if certFile != "" && keyFile != "" {
  		cert, err := helpers.LoadClientCertificate(certFile, keyFile)
  		if err != nil {
  			return err
  		}
  		for _, profile := range p.Profiles {
  			profile.ClientCert = cert
  		}
  		p.Default.ClientCert = cert
  	}
  	return nil
  }
docs: // SetClientCertKeyPairFromFile updates the properties to set client certificates for mutual
  // authenticated TLS remote requests