code: public function getPossibleTypes(AbstractType $abstractType)
      {
          $possibleTypeMap = $this->getPossibleTypeMap();
  
          return isset($possibleTypeMap[$abstractType->name]) ? array_values($possibleTypeMap[$abstractType->name]) : [];
      }
docs: Returns all possible concrete types for given abstract type
  (implementations for interfaces and members of union type for unions)
  
  This operation requires full schema scan. Do not use in production environment.
  
  @return ObjectType[]
  
  @api