Replace LatestValueCache.latest_value property with a get method

The previous commit has introduced the possibility for exceptions to
be raised from the implementation of `latest_value` property.

Properties should ideally not raise, so we replace it with the `get`
method.

Signed-off-by: Sahas Subramanian <[email protected]>

Author: shsms

src/frequenz/sdk/_internal/_channels.py

@@ -44,9 +44,8 @@ def __init__(self, receiver: Receiver[T]) -> None:
         self._latest_value: T | _Sentinel = _Sentinel()
         self._task = asyncio.create_task(self._run())
 
-    @property
-    def latest_value(self) -> T:
-        """The latest value that has been received.
+    def get(self) -> T:
+        """Return the latest value that has been received.
 
         This raises a `ValueError` if no value has been received yet. Use `has_value` to
         check whether a value has been received yet, before trying to access the value,

src/frequenz/sdk/actor/power_distributing/_component_managers/_battery_manager.py

@@ -435,11 +435,10 @@ def _get_battery_inverter_data(
             return None
 
         battery_data = [
-            self._battery_caches[battery_id].latest_value for battery_id in battery_ids
+            self._battery_caches[battery_id].get() for battery_id in battery_ids
         ]
         inverter_data = [
-            self._inverter_caches[inverter_id].latest_value
-            for inverter_id in inverter_ids
+            self._inverter_caches[inverter_id].get() for inverter_id in inverter_ids
         ]
 
         DataType = typing.TypeVar("DataType", BatteryData, InverterData)

src/frequenz/sdk/timeseries/ev_charger_pool/_set_current_bounds.py

@@ -103,7 +103,7 @@ async def _run(self) -> None:
         timer = Timer.timeout(timedelta(self._repeat_interval.total_seconds()))
 
         async for selected in select(bound_chan, timer):
-            meter = meter_data.latest_value
+            meter = meter_data.get()
             if meter is None:
                 raise ValueError("Meter channel closed.")