functions child theme red highlights

<?php

/** Tell WordPress to run post_theme_setup() when the 'after_setup_theme' hook is run. */
add_action( 'after_setup_theme', 'post_theme_setup' );

if ( !function_exists( 'post_theme_setup' ) ):
function post_theme_setup() {

  /* Add our new styles after all other stylesheets have loaded */
  function twentyeleven_enqueue_child_style() {
    wp_enqueue_style( 'child_style', get_stylesheet_directory_uri() . '/custom-style.css', array(), null );
    do_action( 'twentyeleven_enqueue_child_style', 'child_style' );
  }
  add_action( 'wp_enqueue_scripts', 'twentyeleven_enqueue_child_style', 11 );

  /* Remove the default excerpt length for smaller blocks */
  remove_filter( 'excerpt_length', 'twentyeleven_excerpt_length' );

  /* Change the return value for smaller blocks */
  function twentyeleven_child_excerpt_length( $length ) {
    return 20;
  }
  add_filter( 'excerpt_length', 'twentyeleven_child_excerpt_length' );

}
endif;

// The height and width of your custom header. You can hook into the theme's own filters to change these values.
  // Add a filter to twentyten_header_image_width and twentyten_header_image_height to change these values.
  define( 'HEADER_IMAGE_WIDTH', apply_filters( 'twentyeleven_header_image_width', 940 ) );
  define( 'HEADER_IMAGE_HEIGHT', apply_filters( 'twentyeleven_header_image_height', 198 ) );

/** Page Template Sidebar Overwrite Theme Options in Twenty Eleven - change sidebar location */
  function twentyeleven_child_pagetemplates_body_classes( $wp_classes, $extra ){

  $classes = array();

  if( is_page_template( 'sidebar-left-page.php' ) ) :
  // correction for the Left Sidebar Template
    $classes[] = 'left-sidebar';
    $blacklist = array('right-sidebar','singular');
    // Filter the body classes
    foreach( $blacklist as $val ) {
      if (!in_array($val, $wp_classes)) : continue;
      else:
      foreach($wp_classes as $key => $value) {
        if ($value == $val) unset($wp_classes[$key]);
      }
      endif;
    }
  endif;

  if( is_page_template( 'sidebar-right-page.php' ) ) :
  // correction for the Right Sidebar Template
    $classes[] = 'right-sidebar';
    $blacklist = array('left-sidebar','singular');
    // Filter the body classes
    foreach( $blacklist as $val ) {
      if (!in_array($val, $wp_classes)) : continue;
      else:
      foreach($wp_classes as $key => $value) {
        if ($value == $val) unset($wp_classes[$key]);
      }
      endif;
    }
  endif;

return array_merge($wp_classes, (array) $extra, $classes );
}

add_filter( 'body_class', 'twentyeleven_child_pagetemplates_body_classes', 20, 2 );