diff --git a/tools/releasetools/check_target_files_signatures.py b/tools/releasetools/check_target_files_signatures.py
index b9f39a6..9b76954 100755
--- a/tools/releasetools/check_target_files_signatures.py
+++ b/tools/releasetools/check_target_files_signatures.py
@@ -39,6 +39,7 @@
 
 """
 
+import logging
 import os
 import re
 import subprocess
@@ -52,6 +53,8 @@
   sys.exit(1)
 
 
+logger = logging.getLogger(__name__)
+
 # Work around a bug in Python's zipfile module that prevents opening of zipfiles
 # if any entry has an extra field of between 1 and 3 bytes (which is common with
 # zipaligned APKs). This overrides the ZipInfo._decodeExtra() method (which
@@ -415,6 +418,8 @@
     common.Usage(__doc__)
     sys.exit(1)
 
+  common.InitLogging()
+
   ALL_CERTS.FindLocalCerts()
 
   Push("input target_files:")
diff --git a/tools/releasetools/sign_target_files_apks.py b/tools/releasetools/sign_target_files_apks.py
index a07f67f..85897c2 100755
--- a/tools/releasetools/sign_target_files_apks.py
+++ b/tools/releasetools/sign_target_files_apks.py
@@ -102,6 +102,7 @@
 import copy
 import errno
 import gzip
+import logging
 import os
 import re
 import shutil
@@ -121,6 +122,8 @@
   sys.exit(1)
 
 
+logger = logging.getLogger(__name__)
+
 OPTIONS = common.OPTIONS
 
 OPTIONS.extra_apks = {}
@@ -180,11 +183,8 @@
 
   # skipped_prefixes should be one of set/list/tuple types. Other types such as
   # str shouldn't be accepted.
-  assert (isinstance(skipped_prefixes, tuple) or
-          isinstance(skipped_prefixes, set) or
-          isinstance(skipped_prefixes, list)), \
-              "Invalid skipped_prefixes input type: {}".format(
-                  type(skipped_prefixes))
+  assert isinstance(skipped_prefixes, (set, list, tuple)), \
+      "Invalid skipped_prefixes input type: {}".format(type(skipped_prefixes))
 
   compressed_apk_extension = (
       ".apk" + compressed_extension if compressed_extension else None)
@@ -816,7 +816,7 @@
   result = dict()
   for codename in codenames:
     codename = codename.strip()
-    if len(codename) > 0:
+    if codename:
       result[codename] = api_level
   return result
 
@@ -926,6 +926,8 @@
     common.Usage(__doc__)
     sys.exit(1)
 
+  common.InitLogging()
+
   input_zip = zipfile.ZipFile(args[0], "r")
   output_zip = zipfile.ZipFile(args[1], "w",
                                compression=zipfile.ZIP_DEFLATED,