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Device methods that change state (``.set_status``, ``.set_level``,
``.switch_on``, ``.switch_off``, ``.set_color``, ``.set_color_temp``,
``.lock``, ``.unlock``) no longer return ``True`` on success or
``False`` if no ``control_url`` is set. Instead, these methods now
return ``None`` and an exception is raised if no ``control_url`` is set
(where required).