diff --git a/bots/log2zulip b/bots/log2zulip
index 5e1021a..533cd5d 100755
--- a/bots/log2zulip
+++ b/bots/log2zulip
@@ -27,6 +27,7 @@ lock_path = "/var/tmp/log2zulip.lock"
 control_path = "/etc/log2zulip.conf"
 
 def mkdir_p(path):
+    # type: (str) -> None
     # Python doesn't have an analog to `mkdir -p` < Python 3.2.
     try:
         os.makedirs(path)
@@ -37,6 +38,7 @@ def mkdir_p(path):
             raise
 
 def send_log_zulip(file_name, count, lines, extra=""):
+    # type: (str, int, List[str], str) -> None
     content = "%s new errors%s:\n```\n%s\n```" % (count, extra, "\n".join(lines))
     zulip_client.send_message({
         "type": "stream",
@@ -46,6 +48,7 @@ def send_log_zulip(file_name, count, lines, extra=""):
         })
 
 def process_lines(raw_lines, file_name):
+    # type: (List[str], str) -> None
     lines = []
     for line in raw_lines:
         # Add any filtering or modification code here
@@ -61,6 +64,7 @@ def process_lines(raw_lines, file_name):
         send_log_zulip(file_name, len(lines), lines)
 
 def process_logs():
+    # type: () -> None
     for filename in log_files:
         data_file_path = "/var/tmp/log2zulip.state"
     mkdir_p(os.path.dirname(data_file_path))
diff --git a/bots/sync-public-streams b/bots/sync-public-streams
index 08db5da..9cb96af 100755
--- a/bots/sync-public-streams
+++ b/bots/sync-public-streams
@@ -10,9 +10,12 @@ import unicodedata
 sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'api'))
 import zulip
 
+from typing import Set
+
 zulip_client = zulip.Client(client="ZulipSyncPublicStreamsBot/0.1")
 
 def fetch_public_streams():
+    # type: () -> Set[str]
     public_streams = set()
 
     try: