code: private function getSchema()
      {
          if ($this->schema === null) {
              $schemaKey = $this->cachePrefix.'_schema';
              $this->schema = $this->cache->fetch($schemaKey);
              if (empty($this->schema)) {
                  $this->schema = $this->schemaManager->createSchema();
                  $this->cache->save($schemaKey, $this->schema);
              }
          }
  
          return $this->schema;
      }
docs: Returns the schema (from the schema manager or the cache if needed).
  
  @return Schema