From f8e0809b4faa497abfb596480fc4050937754275 Mon Sep 17 00:00:00 2001
From: Joran Angevaare <jorana@nikhef.nl>
Date: Wed, 24 Mar 2021 12:56:53 +0100
Subject: [PATCH] set typing more precisely

---
 strax/context.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/strax/context.py b/strax/context.py
index 34aa51a86..20955f38c 100644
--- a/strax/context.py
+++ b/strax/context.py
@@ -1407,8 +1407,8 @@ def _apply_function(self, data, targets):
     def copy_to_frontend(self,
                          run_id: str,
                          target: str,
-                         target_frontend_id: int = None,
-                         target_compressor: str = None,
+                         target_frontend_id: ty.Optional[int] = None,
+                         target_compressor: ty.Optional[str] = None,
                          rechunk: bool = False):
         """
         Copy data from one frontend to another