code: function isMultipart() {
  		foreach ($this->fields as $field) {
  			if (!$field instanceof Field) {
  				continue;
  			}
  			if ($field->getType() == 'file' || $field->getValueType() == 'file' || $field->getDataType()) {
  				return true;
  			}
  		}
  		return false;
  	}
docs: Checks if the form contains file inputs
  @return boolean