Use properties instead of instance variables in protocol classes

Subtypes just have to emulate this behaviour, so if they have instance
variables instead, they will still satisfy the requirements of the
protocol.

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

Author: shsms

src/frequenz/sdk/timeseries/battery_pool/_result_types.py

@@ -16,14 +16,16 @@
 class BatteryPoolReport(typing.Protocol):
     """A status report for a battery pool."""
 
-    target_power: Power | None
-    """The currently set power for the batteries."""
+    @property
+    def target_power(self) -> Power | None:
+        """The currently set power for the batteries."""
 
-    distribution_result: power_distributing.Result | None
-    """The result of the last power distribution.
+    @property
+    def distribution_result(self) -> power_distributing.Result | None:
+        """The result of the last power distribution.
 
-    This is `None` if no power distribution has been performed yet.
-    """
+        This is `None` if no power distribution has been performed yet.
+        """
 
     @property
     def bounds(self) -> Bounds[Power] | None:

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

@@ -13,14 +13,16 @@
 class EVChargerPoolReport(typing.Protocol):
     """A status report for an EV chargers pool."""
 
-    target_power: Power | None
-    """The currently set power for the EV chargers."""
+    @property
+    def target_power(self) -> Power | None:
+        """The currently set power for the EV chargers."""
 
-    distribution_result: power_distributing.Result | None
-    """The result of the last power distribution.
+    @property
+    def distribution_result(self) -> power_distributing.Result | None:
+        """The result of the last power distribution.
 
-    This is `None` if no power distribution has been performed yet.
-    """
+        This is `None` if no power distribution has been performed yet.
+        """
 
     @property
     def bounds(self) -> Bounds[Power] | None:

src/frequenz/sdk/timeseries/pv_pool/_result_types.py

@@ -13,14 +13,16 @@
 class PVPoolReport(typing.Protocol):
     """A status report for a PV pool."""
 
-    target_power: Power | None
-    """The currently set power for the PV inverters."""
+    @property
+    def target_power(self) -> Power | None:
+        """The currently set power for the PV inverters."""
 
-    distribution_result: power_distributing.Result | None
-    """The result of the last power distribution.
+    @property
+    def distribution_result(self) -> power_distributing.Result | None:
+        """The result of the last power distribution.
 
-    This is `None` if no power distribution has been performed yet.
-    """
+        This is `None` if no power distribution has been performed yet.
+        """
 
     @property
     def bounds(self) -> Bounds[Power] | None: