code: func GetDefaultSigner() (msp.SigningIdentity, error) {
  	signer, err := mspmgmt.GetLocalMSP().GetDefaultSigningIdentity()
  	if err != nil {
  		return nil, errors.WithMessage(err, "error obtaining the default signing identity")
  	}
  
  	return signer, err
  }
docs: // GetDefaultSigner return a default Signer(Default/PERR) for cli