static inheritAttribute(context, callback, attribute) {
    const MpdUtils = shaka.dash.MpdUtils;
    const nodes = MpdUtils.getNodes(context, callback);

    let result = null;
    for (const node of nodes) {
      result = node.attributes[attribute];
      if (result) {
        break;
      }
    }
    return result;
  }
Searches the inheritance for a Segment* with the given attribute.

@param {shaka.dash.DashParser.Context} context
@param {function(?shaka.dash.DashParser.InheritanceFrame):
  ?shaka.extern.xml.Node} callback
  Gets the Element that contains the attribute to inherit.
@param {string} attribute
@return {?string}