exclude category event-calendar

add_action( 'pre_get_posts', 'exclude_events_category' );
function exclude_events_category( $query ) {

  if ( $query->query_vars['eventDisplay'] == 'upcoming' || $query->query_vars['eventDisplay'] == 'past' || $query->query_vars['eventDisplay'] == 'month' && $query->query_vars['post_type'] == TribeEvents::POSTTYPE && !is_tax(TribeEvents::TAXONOMY) && empty( $query->query_vars['suppress_filters'] ) ) {
    $query->set( 'tax_query', array(
      array(
        'taxonomy' => TribeEvents::TAXONOMY,
        'field' => 'slug',
        'terms' => array('atelier-decritures','concours-litteraires'),
        'operator' => 'NOT IN'
      )
    ) );
  }

  return $query;


}