diff --git a/libra/common/faults.py b/libra/common/faults.py
index 6802cca7..61144218 100644
--- a/libra/common/faults.py
+++ b/libra/common/faults.py
@@ -12,7 +12,7 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-from json import dumps
+import json
 
 
 class ServiceFault(object):
diff --git a/libra/common/options.py b/libra/common/options.py
index 25ba00a0..de05c62b 100644
--- a/libra/common/options.py
+++ b/libra/common/options.py
@@ -35,4 +35,4 @@ class Options(object):
 
     def _load_config(self):
         self.config = ConfigParser.ConfigParser()
-        config.readfp(self.args.config)
+        self.config.readfp(self.args.config)
diff --git a/libra/mgm/mgm.py b/libra/mgm/mgm.py
index 013604cf..0d23ccf6 100644
--- a/libra/mgm/mgm.py
+++ b/libra/mgm/mgm.py
@@ -13,8 +13,6 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-import logging
-import argparse
 import daemon
 import signal
 import sys
diff --git a/tox.ini b/tox.ini
index 021b02d9..99de3cec 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py27,pep8
+envlist = py27,pep8,pyflakes
 
 [testenv]
 deps = -r{toxinidir}/tools/pip-requires
@@ -8,3 +8,7 @@ commands = py.test
 
 [testenv:pep8]
 commands = py.test --pep8 -k pep8 --clearcache
+
+[testenv:pyflakes]
+deps = pyflakes
+commands = pyflakes libra