$allowed_post_types = \WPGraphQL::get_allowed_post_types();

if ( ! empty( $allowed_posts_types ) && is_array( $allowed_post_types ) {
  foreach( $allowed_post_types as $post_type ) {
    $post_type_object = get_post_type_object( $post_type );

    if ( $post_type_object instanceof \WP_Post ) {
      // do stuff with $post_type_object.
    }
  }
}

$allowed_post_types = \WPGraphQL::get_allowed_post_types( 'objects' );

foreach( $allowed_post_types as $post_type_object ) {
  // do stuff with $post_type_object
}

This pattern is more readable, easier to test and maintain, and will probably improve some codeclimate scores too.