Doctrine\ODM\MongoDB\Mapping\MappingException::mappingNotFoundByDbName PHP Method

    public static function mappingNotFoundByDbName($className, $dbFieldName)
    {
        return new self("No mapping found for field by DB name '{$dbFieldName}' in class '{$className}'.");
    }

 /**
  * Gets the field mapping by its DB name.
  * E.g. it returns identifier's mapping when called with _id.
  *
  * @param string $dbFieldName
  *
  * @return array
  * @throws MappingException
  */
 public function getFieldMappingByDbFieldName($dbFieldName)
 {
     foreach ($this->fieldMappings as $mapping) {
         if ($mapping['name'] == $dbFieldName) {
             return $mapping;
         }
     }
     throw MappingException::mappingNotFoundByDbName($this->name, $dbFieldName);
 }