Window.kill

>>> window_1 = session.new_window()

>>> window_1 in session.windows
True

>>> window_1.kill()

>>> window_1 not in session.windows
True

>>> one_window_to_rule_them_all = session.new_window()

>>> other_windows = session.new_window(
...     ), session.new_window()

>>> all([w in session.windows for w in other_windows])
True

>>> one_window_to_rule_them_all.kill(all_except=True)

>>> all([w not in session.windows for w in other_windows])
True

>>> one_window_to_rule_them_all in session.windows
True