code: func (m *Manager) GetTxProcessor(channel string) (transaction.TMSTxProcessor, error) {
  	m.mutex.RLock()
  	policyValidator := m.policyValidators[channel]
  	m.mutex.RUnlock()
  	if policyValidator == nil {
  		return nil, errors.Errorf("no policy validator found for channel '%s'", channel)
  	}
  	return &Verifier{IssuingValidator: policyValidator}, nil
  }
docs: // GetTxProcessor returns a TMSTxProcessor that is used to process token transactions.