eZ\Publish\Core\REST\Client\FieldType::getFieldTypeIdentifier PHP Method

    public function getFieldTypeIdentifier()
    {
        return $this->innerFieldType->getFieldTypeIdentifier();
    }

 /**
  * Adds the given $fieldType.
  *
  * Note, this is not an API method and not meant to be used directly!
  *
  * @param FieldType $fieldType
  */
 public function addFieldType(FieldType $fieldType)
 {
     $this->fieldTypes[$fieldType->getFieldTypeIdentifier()] = $fieldType;
 }