remove the default arguments "[]"

remove the default arguments "[]" when the function is defined.
ref: http://docs.python-guide.org/en/latest/writing/gotchas/

Closes-Bug: #1525903
Change-Id: I241f22fe10e535bb50f7ce27fac09d6448fd2bb2

horizon/tables/base.py

@@ -268,7 +268,7 @@ class Column(html.HTMLElement):
     )
 
     def __init__(self, transform, verbose_name=None, sortable=True,
-                 link=None, allowed_data_types=[], hidden=False, attrs=None,
+                 link=None, allowed_data_types=None, hidden=False, attrs=None,
                  status=False, status_choices=None, display_choices=None,
                  empty_value=None, filters=None, classes=None, summation=None,
                  auto=None, truncate=None, link_classes=None, wrap_list=False,
@@ -276,6 +276,7 @@ class Column(html.HTMLElement):
                  update_action=None, link_attrs=None,
                  cell_attributes_getter=None, help_text=None):
 
+        allowed_data_types = allowed_data_types or []
         self.classes = list(classes or getattr(self, "classes", []))
         super(Column, self).__init__()
         self.attrs.update(attrs or {})

openstack_dashboard/dashboards/project/routers/tests.py

@@ -551,7 +551,8 @@ class RouterActionTests(RouterMixin, test.TestCase):
     def test_router_addinterface_exception(self):
         self._test_router_addinterface(raise_error=True)
 
-    def _test_router_addinterface_ip_addr(self, errors=[]):
+    def _test_router_addinterface_ip_addr(self, errors=None):
+        errors = errors or []
         router = self.routers.first()
         subnet = self.subnets.first()
         port = self.ports.first()
@@ -561,7 +562,8 @@ class RouterActionTests(RouterMixin, test.TestCase):
         self._check_router_addinterface(router, subnet, ip_addr)
 
     def _setup_mock_addinterface_ip_addr(self, router, subnet, port,
-                                         ip_addr, errors=[]):
+                                         ip_addr, errors=None):
+        errors = errors or []
         subnet_get = api.neutron.subnet_get(IsA(http.HttpRequest), subnet.id)
         if 'subnet_get' in errors:
             subnet_get.AndRaise(self.exceptions.neutron)

openstack_dashboard/utils/metering.py

@@ -175,7 +175,8 @@ def get_unit(meter, request):
 
 class ProjectAggregatesQuery(object):
     def __init__(self, request, date_from, date_to,
-                 period=None, additional_query=[]):
+                 period=None, additional_query=None):
+        additional_query = additional_query or []
         if not period:
             period = calc_period(date_from, date_to)
         if date_from: