code: public function addChild($structureName, $prefix = '', $suffix = '')
      {
          if (isset($this->children[$structureName])) {
              throw new DefinitionDuplicateException(
                  sprintf('Child structure with same name "%s" already exists', $structureName)
              );
          }
  
          $this->children[$structureName] = array(
              'name' => $structureName,
              'prefix' => (string)$prefix,
              'suffix' => (string)$suffix
          );
      }
docs: Add linked structure definition
  
  @param string $structureName
  @param string $prefix
  @param string $suffix
  
  @throws DefinitionDuplicateException if new definition conflicts with existing one