Classes/Console/Core/Booting/RunLevel.php
private function buildSequence(string $runLevel): Sequence
    {
        if (is_callable([$this, $runLevel])) {
            return $this->{$runLevel}($runLevel);
        }
        throw new InvalidArgumentException('Invalid run level "' . $runLevel . '"', 1402075492);
    }
private function buildSequence(string $runLevel): Sequence
    {
        if (is_callable([$this, $runLevel])) {
            return $this->{$runLevel}($runLevel);
        }
        throw new InvalidArgumentException('Invalid run level "' . $runLevel . '"', 1402075492);
    }
Builds the sequence for the given run level

@param string $runLevel
@throws InvalidArgumentException
@return Sequence