This works fine:
{{ strptime(states('input_datetime.music_alarm'), "%H:%M:%S") - strptime("10", "%M") }}
But this throws an error:
{{ strptime(states('input_datetime.music_alarm'), "%H:%M:%S") + strptime("10", "%M") }}
states(‘input_datetime.music_alarm’) equals a time, like 08:00:00
I’m using jinja2 for homeassistant. Here is the error.
Error doing job: Task exception was never retrieved
Traceback (most recent call last):
File "/usr/lib/python3.5/asyncio/tasks.py", line 239, in _step
result = coro.send(None)
File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/components/automation/__init__.py", line 336, in async_trigger
yield from self._async_action(self.entity_id, variables)
File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/components/automation/__init__.py", line 425, in action
yield from script_obj.async_run(variables)
File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/helpers/script.py", line 158, in async_run
await self._async_call_service(action, variables)
File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/helpers/script.py", line 187, in _async_call_service
self.hass, action, True, variables, validate_config=False)
File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/helpers/service.py", line 72, in async_call_from_config
config[CONF_SERVICE_DATA_TEMPLATE], variables))
File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/helpers/template.py", line 56, in render_complex
for key, item in value.items()}
File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/helpers/template.py", line 56, in <dictcomp>
for key, item in value.items()}
File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/helpers/template.py", line 57, in render_complex
return value.async_render(variables)
File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/helpers/template.py", line 132, in async_render
return self._compiled.render(kwargs).strip()
File "/srv/homeassistant/lib/python3.5/site-packages/jinja2/environment.py", line 1008, in render
return self.environment.handle_exception(exc_info, True)
File "/srv/homeassistant/lib/python3.5/site-packages/jinja2/environment.py", line 780, in handle_exception
reraise(exc_type, exc_value, tb)
File "/srv/homeassistant/lib/python3.5/site-packages/jinja2/_compat.py", line 37, in reraise
raise value.with_traceback(tb)
File "<template>", line 1, in top-level template code
TypeError: bad operand type for unary -: 'datetime.datetime'