protected function setImportedValue($value)
 {
     if ($value !== null && $value != $this->getFixedValue()) {
         $value = null;
         $this->setError(FormControlError::invalid());
     }
     parent::setImportedValue($value);
 }
 function setImportedValue($value)
 {
     if ($this->trim && !$this->hasError()) {
         $value = trim($value);
         if (!$value && !$this->isOptional()) {
             $this->setError(FormControlError::missing());
         }
     }
     if ($this->pattern && !$this->hasError()) {
         if (!preg_match($this->pattern, $value)) {
             $this->setError(FormControlError::wrong());
         }
     }
     parent::setImportedValue($value);
 }