diff --git a/android-interact.sh b/android-interact.sh
index c4b9d2d..858cdc6 100755
--- a/android-interact.sh
+++ b/android-interact.sh
@@ -53,15 +53,11 @@ if [[ $1 == "db" || $1 == "res" ]]; then
 		adb pull $MM_DIR/MicroMsg/$chooseUser/EnMicroMsg.db
 		[[ -f EnMicroMsg.db ]] && \
 			echo "Database successfully downloaded to EnMicroMsg.db" || {
-			>&2 echo "Failed to pull database by adb"
+			>&2 echo "Failed to pull database by adb!"
 			exit 1
 		}
 		adb pull $MM_DIR/MicroMsg/$chooseUser/sfs/avatar.index
-		[[ -f avatar.index ]] && \
-			echo "Avatar index successfully downloaded to avatar.index" || {
-				>&2 echo "Failed to pull avatar index by adb, are you using latest version of wechat?"
-				exit 1
-			}
+		[[ -f avatar.index ]] && echo "Avatar index successfully downloaded to avatar.index"
 	fi
 else
 	echo "Usage: $0 <res|db>"
diff --git a/wechat/msgslice.py b/wechat/msgslice.py
index 2d4d8c4..c80a645 100644
--- a/wechat/msgslice.py
+++ b/wechat/msgslice.py
@@ -1,6 +1,6 @@
 # -*- coding: UTF-8 -*-
 
-class MessageSlicerByTime(object):
+class MessageSlicerByTime:
     """ Separate messages into slices by time,
         for time display in html.
         A new day always begins a new slice.
@@ -28,11 +28,11 @@ class MessageSlicerByTime(object):
         assert len(msgs) == sum([len(k) for k in ret])
         return ret
 
-class MessageSlicerBySize(object):
+class MessageSlicerBySize:
     """ Separate messages into slices by max slice size,
         to avoid too large html.
     """
-    def __init__(self, size=2000):
+    def __init__(self, size=1500):
         """ a slice will have <= 1.5 * cnt messages"""
         self.size = size
         assert self.size > 1