stamenSubstitute = function stamenSubstitute(type) {
    return {
      url: 'http://{s}.basemaps.cartocdn.com/'+ type +'_all/{z}/{x}/{y}.png',
      subdomains: 'abcd',
      minZoom: 0,
      maxZoom: 18,
      attribution: 'Map designs by <a href="http://stamen.com/">Stamen</a>. Data by <a href="http://openstreetmap.org">OpenStreetMap</a>, Provided by <a href="https://carto.com">CARTO</a>'
    };
  }
this is a dummy layer class that modifies the leaflet DOM element background
instead of creating a layer with div