diff --git a/src/utils/communication/comm_utils.py b/src/utils/communication/comm_utils.py
index e2155de5..4ceded5d 100644
--- a/src/utils/communication/comm_utils.py
+++ b/src/utils/communication/comm_utils.py
@@ -1,6 +1,6 @@
 from enum import Enum
 from utils.communication.grpc.main import GRPCCommunication
-from typing import Any, Dict, List, Tuple, TYPE_CHECKING
+from typing import Any, Dict, Union, List, Tuple, TYPE_CHECKING
 # from utils.communication.mpi import MPICommUtils
 # from mpi4py import MPI
 
@@ -54,7 +54,7 @@ def get_rank(self) -> int:
                 "Rank not implemented for communication type", self.comm_type
             )
 
-    def send(self, dest: str | int | List[str | int], data: Any, tag: int = 0):
+    def send(self, dest: Union[str, int, List[Union[str, int]]], data: Any, tag: int = 0):
         if isinstance(dest, list):
             for d in dest:
                 self.comm.send(dest=int(d), data=data)
diff --git a/src/utils/communication/interface.py b/src/utils/communication/interface.py
index 8df3c067..b6c9a8c7 100644
--- a/src/utils/communication/interface.py
+++ b/src/utils/communication/interface.py
@@ -1,5 +1,5 @@
 from abc import ABC, abstractmethod
-from typing import Any, List
+from typing import Any, Union, List
 
 
 class CommunicationInterface(ABC):
@@ -11,7 +11,7 @@ def initialize(self):
         pass
 
     @abstractmethod
-    def send(self, dest: str | int, data: Any):
+    def send(self, dest: Union[str, int], data: Any):
         pass
 
     @abstractmethod