public function lead(): Number
    {
        return $this->reduce(
            new Integer(0),
            static function(Number $lead, Number $number): Number {
                if (!$lead->equals(new Integer(0))) {
                    return $lead;
                }

                return $number;
            }
        );
    }
public function lead(): Number
    {
        return $this->reduce(
            new Integer(0),
            static function(Number $lead, Number $number): Number {
                if (!$lead->equals(new Integer(0))) {
                    return $lead;
                }

                return $number;
            }
        );
    }
public function lead ( ) : Number { return $ this -> reduce ( new Integer ( 0 ) , static function ( Number $ lead , Number $ number ) : Number { if ( ! $ lead -> equals ( new Integer ( 0 ) ) ) { return $ lead ; } return $ number ; } ) ; }
First non zero number found
First non zero number found