Adding PHP code as Text format in Custom Block

Im adding custom block programatically through my custom module. Everything is working fine except when i select PHP code in Text format dropdown it doesn't render php and doesn't show anything when i display block in the website. I wrap whatever content return by php code in a div with a class "custom-block-clss", and when i view page HTML using inspect it does show that div but no content inside. HTML text format is working fine though. When i enter html and select text format as full HTML its showing that html.

Here' the code:

function MYBLOCK_block_info() {
$blocks = array();
$blocks['my_block'] = array(
    'info' => t('My Custom Block'),
);

return $blocks;
}

function MYBLOCK_block_configure($delta='') {
$form = array();

switch($delta) {
    case 'my_block' :
        // Text field form element
        $form['text_body'] = array(
            '#type' => 'text_format',
            '#title' => t('Enter your text here in WYSIWYG format'),
            '#default_value' => variable_get('text_variable', ''),
        );

        break;
}
return $form;
}

function MYBLOCK_block_save($delta = '', $edit = array()) {
switch($delta) {
    case 'my_block' :
        // Saving the WYSIWYG text
        variable_set('text_variable', $edit['text_body']['value']);

        break;
}
}


function MYBLOCK_block_view($delta='') {
$block = array();

switch($delta) {
    case 'my_block' :
        $block['content'] = my_block_view();
        break;
}

return $block;
}


function my_block_view() {
$block = array();

// Capture WYSIWYG text from the variable
$text = variable_get('text_variable', '');

// Block output in HTML with div wrapper
$block = array(
    'message' => array(
        '#prefix' => '<div class="custom-block-clss">',
        '#type' => 'markup',
        '#markup' => $text,
        '#suffix' => '</div>',
    ),
);

return $block;

}

Any help is highly appreciated. Thanks!