public function setLabelAttribute(string $name, ?string $value)
  {
    if ($value==='' || $value===null)
    {
      unset($this->labelAttributes[$name]);
    }
    else
    {
      if ($name=='class' && isset($this->labelAttributes[$name]))
      {
        $this->labelAttributes[$name] .= ' ';
        $this->labelAttributes[$name] .= $value;
      }
      else
      {
        $this->labelAttributes[$name] = $value;
      }
    }
  }