public static function fromString($startTime, $endTime): self
    {
        return new static(TimeBuilder::fromString($startTime), TimeBuilder::fromString($endTime));
    }
public static function fromString($startTime, $endTime): self
    {
        return new static(TimeBuilder::fromString($startTime), TimeBuilder::fromString($endTime));
    }
public static function fromString ( $ startTime , $ endTime ) : self { return new static ( TimeBuilder :: fromString ( $ startTime ) , TimeBuilder :: fromString ( $ endTime ) ) ; }
Create a new interval from time strings.

@param string $startTime The start time
@param string $endTime The end time
@return TimeInterval
@throws \InvalidArgumentException
Create a new interval from time strings .