Replaced dict.setdefault() usage to avoid unnecessary object instantiations.

django/contrib/postgres/forms/ranges.py

@@ -15,8 +15,10 @@ class BaseRangeField(forms.MultiValueField):
     }
 
     def __init__(self, **kwargs):
-        kwargs.setdefault('widget', RangeWidget(self.base_field.widget))
-        kwargs.setdefault('fields', [self.base_field(required=False), self.base_field(required=False)])
+        if 'widget' not in kwargs:
+            kwargs['widget'] = RangeWidget(self.base_field.widget)
+        if 'fields' not in kwargs:
+            kwargs['fields'] = [self.base_field(required=False), self.base_field(required=False)]
         kwargs.setdefault('required', False)
         kwargs.setdefault('require_all_fields', False)
         super(BaseRangeField, self).__init__(**kwargs)

django/template/backends/jinja2.py

@@ -26,8 +26,9 @@ class Jinja2(BaseEngine):
         environment = options.pop('environment', 'jinja2.Environment')
         environment_cls = import_string(environment)
 
+        if 'loader' not in options:
+            options['loader'] = jinja2.FileSystemLoader(self.template_dirs)
         options.setdefault('autoescape', True)
-        options.setdefault('loader', jinja2.FileSystemLoader(self.template_dirs))
         options.setdefault('auto_reload', settings.DEBUG)
         options.setdefault('undefined',
                            jinja2.DebugUndefined if settings.DEBUG else jinja2.Undefined)

django/test/client.py

@@ -146,7 +146,9 @@ def store_rendered_templates(store, signal, sender, template, context, **kwargs)
     of rendering.
     """
     store.setdefault('templates', []).append(template)
-    store.setdefault('context', ContextList()).append(copy(context))
+    if 'context' not in store:
+        store['context'] = ContextList()
+    store['context'].append(copy(context))
 
 
 def encode_multipart(boundary, data):

django/utils/formats.py

@@ -94,7 +94,9 @@ def get_format_modules(lang=None, reverse=False):
     """
     if lang is None:
         lang = get_language()
-    modules = _format_modules_cache.setdefault(lang, list(iter_format_modules(lang, settings.FORMAT_MODULE_PATH)))
+    if lang not in _format_modules_cache:
+        _format_modules_cache[lang] = list(iter_format_modules(lang, settings.FORMAT_MODULE_PATH))
+    modules = _format_modules_cache[lang]
     if reverse:
         return list(reversed(modules))
     return modules