code: func (s *SessionClient) UserLogin(ctx context.Context, email, passphrase string) error {
  	// Package up login credentials for the user
  	login := apitypes.UserLogin{
  		Email:    email,
  		Password: passphrase,
  	}
  
  	rawLogin, err := json.Marshal(login)
  	if err != nil {
  		return err
  	}
  
  	return performLogin(ctx, s, "user", rawLogin)
  }
docs: // UserLogin logs the user in using the provided email and passphrase