original_string: public function groupBy($column, $orderMode = null)
  	{
  		$columnObj    = $this->factory->references('Column', $column);
  		$orderModeObj = ($orderMode) ? $this->factory->references('OrderModeEnum', $orderMode) : null;
  		$this->select->groupBy($columnObj, $orderModeObj);
  
  		return $this;
  	}
code: public function groupBy($column, $orderMode = null)
  	{
  		$columnObj    = $this->factory->references('Column', $column);
  		$orderModeObj = ($orderMode) ? $this->factory->references('OrderModeEnum', $orderMode) : null;
  		$this->select->groupBy($columnObj, $orderModeObj);
  
  		return $this;
  	}
code_tokens: public function groupBy ( $ column , $ orderMode = null ) { $ columnObj = $ this -> factory -> references ( 'Column' , $ column ) ; $ orderModeObj = ( $ orderMode ) ? $ this -> factory -> references ( 'OrderModeEnum' , $ orderMode ) : null ; $ this -> select -> groupBy ( $ columnObj , $ orderModeObj ) ; return $ this ; }
docstring: Add a group by expression to the query.
  
  @param string      $column
  @param string|null $orderMode
  
  @return $this The same instance to concatenate methods
docstring_tokens: Add a group by expression to the query .