Get Related Author Posts

function t4b_get_related_author_posts() {
    global $authordata, $post;
    if(get_post_type() == 'quick-tips') {
        $post_type = 'quick-tips';
    } else { $post_type = 'post'; }
    $authors_posts = get_posts( array( 'author' => $authordata->ID, 'post_type' => $post_type, 'post__not_in' => array( $post->ID ), 'posts_per_page' => 1 ) );
    if($authors_posts) :
    $output = '<div id="t4b-latest-tune">';
    foreach ( $authors_posts as $authors_post ) {
        $post_date = $authors_post->post_date;
        $post_date = mysql2date('M j, Y g:i:s a', $post_date);
        $postDate = $authors_post->post_date;
        $hide_extra = get_date_time_count($postDate);
        if ( has_post_thumbnail() ) {
            $output .= get_the_post_thumbnail($authors_post->ID, 'sidebar-thumb');
        } else {
            $output .= '<img src="'.get_stylesheet_directory_uri().'/images/wp-logo.png" alt="TiPS4BLOG" />';
        }
        $output .= '<h4><a href="' . get_permalink( $authors_post->ID ) . '">';
        $output .= apply_filters( 'the_title', $authors_post->post_title, $authors_post->ID ) . '</a></h4>';
        $output .= '<p>' . $post_date . ' ( ' . $hide_extra . ' আগে )</p>';
    }
    $output .= '</div>';
    else :
        $output = '<div id="t4b-empty-tune">';
        $output .= '<h4>*** এই ব্লগে এটাই আমার প্রথম টিপস ***</h4>';
        $output .= '</div>';
    endif;
    return $output;
}