lib/Jejik/MT940/Reader.php
public function setContraAccountClass($contraAccountClass)
    {
        if (!is_callable($contraAccountClass) && !class_exists($contraAccountClass)) {
            throw new \InvalidArgumentException('$contraAccountClass must be a valid classname or a PHP callable');
        }

        $this->contraAccountClass = $contraAccountClass;
        return $this;
    }
public function setContraAccountClass($contraAccountClass)
    {
        if (!is_callable($contraAccountClass) && !class_exists($contraAccountClass)) {
            throw new \InvalidArgumentException('$contraAccountClass must be a valid classname or a PHP callable');
        }

        $this->contraAccountClass = $contraAccountClass;
        return $this;
    }
Set the classname of the contraAccount class or callable that returns an object that
implements the AccountInterface.

The callable is passed the account number as a parameter. Example:

$reader->setContraAccountClass(function ($accountNumber) {
return new My\ContraAccount();
});

@param string|callable $contraAccountClass
@return $this