diff --git a/tacker/api/api_common.py b/tacker/api/api_common.py
index 55141a2cb..980aff0a5 100644
--- a/tacker/api/api_common.py
+++ b/tacker/api/api_common.py
@@ -26,7 +26,7 @@ from tacker.openstack.common import log as logging
 LOG = logging.getLogger(__name__)
 
 
-def get_filters(request, attr_info, skips=[]):
+def get_filters(request, attr_info, skips=None):
     """Extracts the filters from the request string.
 
     Returns a dict of lists for the filters:
@@ -35,6 +35,8 @@ def get_filters(request, attr_info, skips=[]):
     {'check': [u'a', u'b'], 'name': [u'Bob']}
     """
     res = {}
+    if skips is None:
+        skips = []
     for key, values in request.GET.dict_of_lists().iteritems():
         if key in skips:
             continue
diff --git a/tacker/openstack/common/db/exception.py b/tacker/openstack/common/db/exception.py
index 436cc8626..409530cf9 100644
--- a/tacker/openstack/common/db/exception.py
+++ b/tacker/openstack/common/db/exception.py
@@ -30,8 +30,8 @@ class DBError(Exception):
 
 class DBDuplicateEntry(DBError):
     """Wraps an implementation specific exception."""
-    def __init__(self, columns=[], inner_exception=None):
-        self.columns = columns
+    def __init__(self, columns=None, inner_exception=None):
+        self.columns = columns if columns else []
         super(DBDuplicateEntry, self).__init__(inner_exception)
 
 
diff --git a/tacker/tests/unit/extension_stubs.py b/tacker/tests/unit/extension_stubs.py
index cfec4dfd0..5c11fe024 100644
--- a/tacker/tests/unit/extension_stubs.py
+++ b/tacker/tests/unit/extension_stubs.py
@@ -43,8 +43,9 @@ class StubExtension(object):
 
 class StubPlugin(object):
 
-    def __init__(self, supported_extensions=[]):
-        self.supported_extension_aliases = supported_extensions
+    def __init__(self, supported_extensions=None):
+        self.supported_extension_aliases = supported_extensions \
+            if supported_extensions else []
 
 
 class ExtensionExpectingPluginInterface(StubExtension):
diff --git a/tacker/tests/unit/test_api_v2.py b/tacker/tests/unit/test_api_v2.py
index d32a1e7d6..a9fcd0ed8 100644
--- a/tacker/tests/unit/test_api_v2.py
+++ b/tacker/tests/unit/test_api_v2.py
@@ -134,9 +134,11 @@ class APIv2TestCase(APIv2TestBase):
         fields.extend(policy_attrs)
         return fields
 
-    def _get_collection_kwargs(self, skipargs=[], **kwargs):
+    def _get_collection_kwargs(self, skipargs=None, **kwargs):
         args_list = ['filters', 'fields', 'sorts', 'limit', 'marker',
                      'page_reverse']
+        if skipargs is None:
+            skipargs = []
         args_dict = dict((arg, mock.ANY)
                          for arg in set(args_list) - set(skipargs))
         args_dict.update(kwargs)
diff --git a/tacker/vm/infra_drivers/heat/heat.py b/tacker/vm/infra_drivers/heat/heat.py
index a0a35e2ea..09eac54a5 100644
--- a/tacker/vm/infra_drivers/heat/heat.py
+++ b/tacker/vm/infra_drivers/heat/heat.py
@@ -160,8 +160,10 @@ class DeviceHeat(abstract_driver.DeviceAbstractDriver):
                 }
             }
 
-        def handle_port_creation(network_param, ip_list=[],
+        def handle_port_creation(network_param, ip_list=None,
                                  mgmt_port=False):
+            if ip_list is None:
+                ip_list = []
             port = '%s-%s-port' % (vdu_id, network_param['network'])
             port_dict = make_port_dict()
             if mgmt_port: