WordPress: Checkbox Class

class checkbox_platform{

  public static function getPlatform(){
    	$template_swplatform = array(
                   	'Windows' => 'Windows',
		'Mac' => 'Mac',
		'Linux' => 'Linux',
		'Unix' => 'Unix'
               	);
    	return $template_swplatform;
  	}
 }
 
 
 /* paste below in content section */
 <?php
foreach ( checkbox_platform::getPlatform() as $key=>$value){
?>
                 <input type="checkbox" name="sw_platform[]" value="<?php echo $key; ?>"

<?php
checked($sw_platform, 1);
?>
                ><?php echo $value; ?><br>
<?php   }  ?>