code/libraries/joomlatools/library/exception/handler/abstract.php
public function addExceptionCallback(callable $callback, $prepend = false )
    {
        if($prepend) {
            array_unshift($this->__exception_callbacks, $callback);
        } else {
            array_push($this->__exception_callbacks, $callback);
        }

        return $this;
    }
public function addExceptionCallback(callable $callback, $prepend = false )
    {
        if($prepend) {
            array_unshift($this->__exception_callbacks, $callback);
        } else {
            array_push($this->__exception_callbacks, $callback);
        }

        return $this;
    }
public function addExceptionCallback ( callable $ callback , $ prepend = false ) { if ( $ prepend ) { array_unshift ( $ this -> __exception_callbacks , $ callback ) ; } else { array_push ( $ this -> __exception_callbacks , $ callback ) ; } return $ this ; }
Add an exception callback

@param  callable $callback
@param  bool $prepend If true, the callback will be prepended instead of appended.
@throws \InvalidArgumentException If the callback is not a callable
@return KExceptionHandlerAbstract
Add an exception callback