def fillup_layer(layer, first_clbit):
        """
        Given a layer, replace the Nones in it with EmptyWire elements.
        Args:
            layer (list): The layer that contains Nones.
            first_clbit (int): The first wire that is classic.

        Returns:
            list: The new layer, with no Nones.
        """
        for nones in [i for i, x in enumerate(layer) if x is None]:
            layer[nones] = EmptyWire('═') if nones >= first_clbit else EmptyWire('─')
        return layer
Given a layer, replace the Nones in it with EmptyWire elements.
        Args:
            layer (list): The layer that contains Nones.
            first_clbit (int): The first wire that is classic.

        Returns:
            list: The new layer, with no Nones.