code: public function addDebug($value){
  		$bt = debug_backtrace();
  		//false or null become nullstring ''
  		$info = sprintf('%s() at line %d in %s',$bt[1]['function'],$bt[1]['line'],$bt[1]['file']);
  		$this->debug[] = array($bt[1]['function'],$bt[1]['line'],$bt[1]['file'],(($value === false) || (is_null($value))) ? '' : $value);
  		unset($bt);
  		return $this;
  	}
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