Fix a bug that caused a busy loop without peers

node.py

@@ -145,6 +145,8 @@ def heartbeat(node):
         for i, peer in enumerate(node.peers):
             wait_until(start_time + 60 * (i+1) / peer_count)
             send_heartbeat(node, peer)
+        if len(node.peers) == 0:
+            time.sleep(60)
 
 def receiver(node):
     while True:
@@ -192,7 +194,7 @@ def main():
             log(f"Default port {DEFAULT_PORT} is in use, listening on port {port} instead.")
         else:
             raise e
-    
+
     log("Node is ready")
 
     node = Node(node_socket, peers)