def METHOD_NAME(self, item):
    # TODO: ListView only has built-in support for one icon per row. One possible
    # workaround is in https://stackoverflow.com/a/46128593.
    def strip_icon(item, attr):
        val = getattr(item, attr, None)
        if isinstance(val, toga.Widget):
            warn("This backend does not support the use of widgets in cells")
            val = None
        if isinstance(val, tuple):
            val = val[1]
        if val is None:
            val = self.interface.missing_value
        return str(val)
    return [strip_icon(item, attr) for attr in self.interface._accessors]