How to use the esri-leaflet.Util._updateMapAttribution function in esri-leaflet

_asyncAdd: function () {
    var map = this._map;
    if (map.attributionControl) {
      if (this._customTileset) {
        if (this._copyrightText) {
          // pull static copyright text for services published with Pro
          map.attributionControl.addAttribution('<span class="esri-dynamic-attribution">' + this._copyrightText + '</span>');
        }
      } else {
        // provide dynamic attribution for Esri basemaps
        Util._getAttributionData('https://static.arcgis.com/attribution/World_Street_Map', map);
        map.attributionControl.addAttribution('<span class="esri-dynamic-attribution">USGS, NOAA</span>');
        map.on('moveend', Util._updateMapAttribution);
      }
    }

    // set the background color of the map to the background color of the tiles
    map.getContainer().style.background = this._mapboxGL.options.style.layers[0].paint['background-color'];
    this._mapboxGL.addTo(map, this);
  }
});

_asyncAdd: function () {
    var map = this._map;
    // thought it was just me, but apparently its not easy to mixin two different styles
    // https://github.com/mapbox/mapbox-gl-js/issues/4000

    // set the background color of the map to the background color of the tiles
    map.getContainer().style.background = this._mapboxGL.options.style.layers[0].paint['background-color'] || '#e1e3d0';

    map.on('moveend', Util._updateMapAttribution);
    this._mapboxGL.addTo(map, this);
    // map._gl = this._mapboxGL;
  }
});

onRemove: function (map) {
    map.off('moveend', Util._updateMapAttribution);
    map.removeLayer(this._mapboxGL);

    if (map.attributionControl) {
      var vectorAttribution = document.getElementsByClassName('esri-dynamic-attribution')[0].outerHTML;
      // this doesn't work, not sure why.
      map.attributionControl.removeAttribution(vectorAttribution);
    }
  },

onRemove: function (map) {
    map.off('moveend', Util._updateMapAttribution);
    map.removeLayer(this._mapboxGL);

    if (map.attributionControl) {
      var vectorAttribution = document.getElementsByClassName('esri-dynamic-attribution')[0].outerHTML;
      // this doesn't work, not sure why.
      map.attributionControl.removeAttribution(vectorAttribution);
    }
  },