Using $_SESSION to Display Errors

display-session-errors.php

if ( array_key_exists( 'my_plugin_errors', $_SESSION ) ) {
    foreach( $_SESSION['my_plugin_errors'] as $error ) {?>
        <div class="error"><p>
            <?php echo $error; ?>
        </p></div><?php
    }
    unset( $_SESSION['my_plugin_errors'] );
}

save-errors-session.php

if ( ! empty( $errors ) ) {
    $_SESSION['my_plugin_errors'] = $errors;
}

start-session.php

if ( !session_id() ) {
    session_start();
}