original_string: public function getNodeById($id)
      {
          if (empty($this->nodes[$id])) {
              throw new \InvalidArgumentException("Invalid node primary key $id");
          }
          return $this->nodes[$id];
      }
code: public function getNodeById($id)
      {
          if (empty($this->nodes[$id])) {
              throw new \InvalidArgumentException("Invalid node primary key $id");
          }
          return $this->nodes[$id];
      }
code_tokens: public function getNodeById ( $ id ) { if ( empty ( $ this -> nodes [ $ id ] ) ) { throw new \ InvalidArgumentException ( "Invalid node primary key $id" ) ; } return $ this -> nodes [ $ id ] ; }
docstring: Returns a single node from the tree, identified by its ID.
  
  @param int $id Node ID
  
  @throws \InvalidArgumentException
  
  @return Node
docstring_tokens: Returns a single node from the tree identified by its ID .