diff --git a/install/helioviewer/hvpull/browser/basebrowser.py b/install/helioviewer/hvpull/browser/basebrowser.py
index 0e5b4122..ef5de03a 100644
--- a/install/helioviewer/hvpull/browser/basebrowser.py
+++ b/install/helioviewer/hvpull/browser/basebrowser.py
@@ -1,4 +1,7 @@
 """Base data browser definition"""
+from typing import Callable, Optional
+
+
 class BaseDataBrowser:
     """BaseDataBrowser"""
     def __init__(self, server):
@@ -7,8 +10,8 @@ def __init__(self, server):
     def get_directories(self, start_time, end_time):
         """Gets a list of directories to be queried for the given time range"""
         return None
-    
-    def get_files(self, uri, extension, filter_func: callable | None = None):
+
+    def get_files(self, uri, extension, filter_func: Optional[Callable] = None):
         """Get all the files that end with specified extension at the uri"""
         return None
     
diff --git a/install/helioviewer/hvpull/browser/httpbrowser.py b/install/helioviewer/hvpull/browser/httpbrowser.py
index 47d91e4b..8fee7af8 100644
--- a/install/helioviewer/hvpull/browser/httpbrowser.py
+++ b/install/helioviewer/hvpull/browser/httpbrowser.py
@@ -2,6 +2,7 @@
 import sys
 import os
 import socket
+from typing import Callable, Optional
 from helioviewer.hvpull.browser.basebrowser import BaseDataBrowser, NetworkError
 
 if (sys.version_info >= (3, 0)):
@@ -81,7 +82,7 @@ def get_directories(self, start_date, end_date):
         # filter(lambda url: url.endswith("/"), self._query(location))
         return self.server.compute_directories(start_date, end_date)
 
-    def get_files(self, location, extension, filter_func: callable | None = None):
+    def get_files(self, location, extension, filter_func: Optional[Callable] = None):
         """Get all the files that end with specified extension at the uri"""
         files = None
         num_retries = 0
diff --git a/install/helioviewer/hvpull/browser/localbrowser.py b/install/helioviewer/hvpull/browser/localbrowser.py
index bc39bb99..ef347479 100644
--- a/install/helioviewer/hvpull/browser/localbrowser.py
+++ b/install/helioviewer/hvpull/browser/localbrowser.py
@@ -1,5 +1,6 @@
 """Local data browser"""
 import os
+from typing import Callable, Optional
 from helioviewer.hvpull.browser.basebrowser import BaseDataBrowser
 
 
@@ -14,7 +15,7 @@ def get_directories(self, start_date, end_date):
         """Get a list of directories at the passed uri"""
         return self.server.compute_directories(start_date, end_date)
 
-    def get_files(self, location, extension, filter_func: callable | None = None):
+    def get_files(self, location, extension, filter_func: Optional[Callable] = None):
         """Get all the files that end with specified extension at the uri"""
 
         # ensure the location exists