src/Khayyam/Khayyam.php
public function average(Carbon $dt = null)
    {
        $dt = ($dt === null) ? static::now($this->tz) : $dt;

        return $this->addSeconds((int) ($this->diffInSeconds($dt, false) / 2));
    }
public function average(Carbon $dt = null)
    {
        $dt = ($dt === null) ? static::now($this->tz) : $dt;

        return $this->addSeconds((int) ($this->diffInSeconds($dt, false) / 2));
    }
Modify the current instance to the average of a given instance (default now) and the current instance.

@param Carbon $dt

@return static