Returns a list of all the layers in the packet that are of the layer type (an incase-sensitive string).
        This is in order to retrieve layers which appear multiple times in the same packet (i.e. double VLAN) which cannot be
        retrieved by easier means.

def get_multiple_layers(self, layer_name):
        """
        Returns a list of all the layers in the packet that are of the layer type (an incase-sensitive string).
        This is in order to retrieve layers which appear multiple times in the same packet (i.e. double VLAN) which cannot be
        retrieved by easier means.
        """
        return [layer for layer in self.layers if layer.layer_name.lower() == layer_name.lower()]