code: def backward_char(event):
      " Move back a character. "
      buff = event.current_buffer
      buff.cursor_position += buff.document.get_cursor_left_position(count=event.argf backward_char(event):
      " Move back a character. "
      buff = event.current_buffer
      buff.cursor_position += buff.document.get_cursor_left_position(count=event.arg)
docs: Move back a character.