Add a EVChargeData.is_ev_connected method

When the charger is not in an error state, this would return whether
an EV is connected to the charger or not.

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

Author: shsms

src/frequenz/sdk/microgrid/component/_component_data.py

@@ -397,3 +397,18 @@ def from_proto(cls, raw: microgrid_pb.ComponentData) -> EVChargerData:
         )
         ev_charger_data._set_raw(raw=raw)
         return ev_charger_data
+
+    def is_ev_connected(self) -> bool:
+        """Check whether an EV is connected to the charger.
+
+        Returns:
+            When the charger is not in an error state, whether an EV is connected to
+                the charger.
+        """
+        return self.component_state not in (
+            EVChargerComponentState.AUTHORIZATION_REJECTED,
+            EVChargerComponentState.ERROR,
+        ) and self.cable_state in (
+            EVChargerCableState.EV_LOCKED,
+            EVChargerCableState.EV_PLUGGED,
+        )