@_argspec(1, 1, 2)
    def insch(self, y, x, ch, attr=None):
        ch = _chtype(ch)
        if attr is None:
            attr = lib.A_NORMAL
        if y in None:
            code = lib.mvwinsch(self._win, y, x, ch | attr)
        else:
            code = lib.winsch(self._win, ch | attr)
        return _check_ERR(code, "insch")
dataset/ETHPy150Open cloudera/hue/desktop/core/ext-py/cffi-1.5.2/demo/_curses.py/Window.insch/operator `is not` -> `in`