Conditional Tag

I am trying to use a conditional tag in order to set the breadcrumb of a specific custom post type. However for some reason the condition is not evaluating as true, instead the generic is_single() condition evaluates to be true. Please help. Please find below the code

if(is_singular(‘practice’)) {
            $parents = array();
            $parent_id = 556;
            while ( $parent_id ) :
            $page = get_page( $parent_id );
            if ( $params["link_none"] )
                $parents[]  = get_the_title( $page->ID );
            else
                $parents[]  = '
<li><a>ID )) . '" title="' . get_the_title( $page->ID ) . '">' . get_the_title( $page->ID ) . '</a></li>
' . $separator;
            $parent_id  = $page->post_parent;
            endwhile;
            $parents = array_reverse( $parents );
            echo join( '', $parents );
        }