Fix bug in grpc logic

python/unityagents/rpc_communicator.py

 
 
 class UnityToExternalServicerImplementation(UnityToExternalServicer):
-    parent_conn, child_conn = Pipe()
+    def __init__(self):
+        self.parent_conn, self.child_conn = Pipe()
+
 
     def Initialize(self, request, context):
         self.child_conn.send(request)