code: def layer_uri(self, layer_name):
          
          layers = self.layers()
          for layer, extension in product(layers, EXTENSIONS):
              one_file = QFileInfo(
                  self.uri.filePath(layer + '.' + extension))
              if one_file.exists():
                  if one_file.baseName() == layer_name:
                      return one_file.absoluteFilePath()
          else:
              return None
docs: Get layer URI.
  
          :param layer_name: The name of the layer to fetch.
          :type layer_name: str
  
          :return: The URI to the layer.
          :rtype: str
  
          .. versionadded:: 4.0