diff --git a/jedi/debug.py b/jedi/debug.py
index 72259842..2b2bcfb8 100644
--- a/jedi/debug.py
+++ b/jedi/debug.py
@@ -1,6 +1,7 @@
 import os
 import time
 from contextlib import contextmanager
+from typing import Callable, Optional
 
 _inited = False
 
@@ -62,7 +63,7 @@ enable_warning = False
 enable_notice = False
 
 # callback, interface: level, str
-debug_function = None
+debug_function: Optional[Callable[[str, str], None]] = None
 _debug_indent = 0
 _start_time = time.time()
 
diff --git a/setup.cfg b/setup.cfg
index 0c78a591..a9379444 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -57,8 +57,3 @@ strict_equality = True
 [mypy-jedi,jedi.inference.compiled,jedi.inference.value]
 # Various __init__.py files which contain re-exports we want to implicitly make.
 implicit_reexport = True
-
-[mypy-jedi.debug]
-# jedi.debug is configured by setting module-level values, which mypy doesn't
-# know about. See https://github.com/python/mypy/issues/9209.
-warn_unreachable = False