add bool function to queue

evrouting/charge/routing.py

@@ -52,12 +52,8 @@ def shortest_path(G: nx.Graph, charging_stations: set, s: Node, t: Node,
     prio_queue = PriorityQueue()
     prio_queue.insert(s, priority=0, count=0)
 
-    while True:
-        try:
-            minimum_node: Node = prio_queue.peak_min()
-        except KeyError:
-            # empty queue
-            break
+    while prio_queue:
+        minimum_node: Node = prio_queue.peak_min()
 
         label_minimum_node: Label = l_uns[minimum_node].delete_min()
         l_set[minimum_node].add(label_minimum_node)
@@ -65,7 +61,7 @@ def shortest_path(G: nx.Graph, charging_stations: set, s: Node, t: Node,
         if minimum_node == t:
             return f_soc_factory(label_minimum_node).minimum
 
-        # handle charging stations
+        # Handle charging stations
         if minimum_node in charging_stations and \
                 not minimum_node == label_minimum_node.last_cs:
             f_soc: SoCFunction = f_soc_factory(label_minimum_node)
@@ -75,6 +71,7 @@ def shortest_path(G: nx.Graph, charging_stations: set, s: Node, t: Node,
                 capacity=capacity)
 
             if t_charge is not None:
+                # Spawn new label at t_charge
                 l_uns[minimum_node].insert(
                     Label(
                         t_trip=label_minimum_node.t_trip + t_charge,

evrouting/utils.py

@@ -48,3 +48,12 @@ class PriorityQueue:
             else:
                 heappop(self.pq)
         raise KeyError('Empty queue.')
+
+    def __bool__(self) -> bool:
+        """Check if empty."""
+        try:
+            self.peak_min()
+        except KeyError:
+            return False
+
+        return True