$s1 = 'ATGGTAC';   
$s2 =       'CCGTAATG';

$result12 = merged_function($s1,$2);

# Should return: "ATGGTACCGTAATG'

##</code><code>##

$s1 = 'CCGTAATG';
$s2 =      'ATGGTAC';   


$result12 = merged_function($s1,$2);

# Should return: "CCGTAATGGTAC'