Unexpected Error when calling service

I’m using the Developer Tools to call the input_select.select_option service. My yaml looks like this:

service: input_select.select_option
data:
  option: "Off"

It’s very straight forward. However, the call service button is grayed out and when I try to hit it anyway, I get the following error:

2021-08-21 00:31:23 ERROR (MainThread) [homeassistant.helpers.script.websocket_api_script] websocket_api script: Error executing script. Unexpected error for call_service at pos 1: sequence item 0: expected str instance, Optional found
Traceback (most recent call last):
File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 371, in _async_step
await getattr(self, handler)()
File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 571, in _async_call_service_step
await service_task
File "/usr/src/homeassistant/homeassistant/core.py", line 1445, in async_call
processed_data = handler.schema(service_data)
File "/usr/local/lib/python3.9/site-packages/voluptuous/schema_builder.py", line 272, in __call__
return self._compiled([], data)
File "/usr/local/lib/python3.9/site-packages/voluptuous/validators.py", line 215, in _run
return self._exec(self._compiled, value, path)
File "/usr/local/lib/python3.9/site-packages/voluptuous/validators.py", line 339, in _exec
v = func(path, v)
File "/usr/local/lib/python3.9/site-packages/voluptuous/schema_builder.py", line 817, in validate_callable
return schema(data)
File "/usr/src/homeassistant/homeassistant/helpers/config_validation.py", line 134, in validate
raise vol.Invalid("must contain at least one of {}.".format(", ".join(keys)))
TypeError: sequence item 0: expected str instance, Optional found
2021-08-21 00:31:23 ERROR (MainThread) [homeassistant.components.websocket_api.http.connection] [140385006213536] Error handling message: Unknown error
Traceback (most recent call last):
File "/usr/src/homeassistant/homeassistant/components/websocket_api/decorators.py", line 25, in _handle_async_response
await func(hass, connection, msg)
File "/usr/src/homeassistant/homeassistant/components/websocket_api/commands.py", line 525, in handle_execute_script
await script_obj.async_run(msg.get("variables"), context=context)
File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 1219, in async_run
await asyncio.shield(run.async_run())
File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 353, in async_run
await self._async_step(log_exceptions=False)
File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 371, in _async_step
await getattr(self, handler)()
File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 571, in _async_call_service_step
await service_task
File "/usr/src/homeassistant/homeassistant/core.py", line 1445, in async_call
processed_data = handler.schema(service_data)
File "/usr/local/lib/python3.9/site-packages/voluptuous/schema_builder.py", line 272, in __call__
return self._compiled([], data)
File "/usr/local/lib/python3.9/site-packages/voluptuous/validators.py", line 215, in _run
return self._exec(self._compiled, value, path)
File "/usr/local/lib/python3.9/site-packages/voluptuous/validators.py", line 339, in _exec
v = func(path, v)
File "/usr/local/lib/python3.9/site-packages/voluptuous/schema_builder.py", line 817, in validate_callable
return schema(data)
File "/usr/src/homeassistant/homeassistant/helpers/config_validation.py", line 134, in validate
raise vol.Invalid("must contain at least one of {}.".format(", ".join(keys)))
TypeError: sequence item 0: expected str instance, Optional found

Please help. I’m very new to this. Thank you.

You have not specified which input select. Give it an entity_id, like this:

service: input_select.select_option
target:
  entity_id: input_select.chime_type
data:
  option: 'Cuckoo'