@@ -64,15 +64,19 @@
         """
         Many imports can be made for a single import statement. This method
         help the management of this aspect.
         """
 
-    def __call__(self, name, globals={}, locals={}, fromlist=[], level=-1):
+    def __call__(self, name, globals=None, locals=None,
+		 fromlist=None, level=-1):
         """
         The import method itself.
         """
-        return _STANDARD_PYTHON_IMPORTER(name, globals, locals, fromlist,
+        return _STANDARD_PYTHON_IMPORTER(name,
+					 globals,
+					 locals,
+					 fromlist,
                                          level)
 
     def end(self):
         """
         Needed for clean up.
@@ -95,16 +99,21 @@
         self._tl._modules_loaded = None
 
     def begin(self):
         self._tl._modules_loaded = set()
 
-    def __call__(self, name, globals={}, locals={}, fromlist=[], level=-1):
+    def __call__(self, name, globals=None, locals=None,
+		 fromlist=None, level=-1):
         """
         The import method itself.
         """
 
-        call_begin_end = self._tl._modules_loaded == None
+	globals = globals or {}
+	locals = locals or {}
+	fromlist = fromlist or []
+
+        call_begin_end = self._tl._modules_loaded is None
         if call_begin_end:
             self.begin()
 
 	try:
             self._tl.globals = globals
@@ -240,15 +249,20 @@
         if file_path.startswith(self.__web2py_path_os_path_sep):
             file_path = file_path[self.__web2py_path_os_path_sep_len:]
             return self.__RE_APP_DIR.match(file_path)
         return False
 
-    def __call__(self, name, globals={}, locals={}, fromlist=[], level=-1):
+    def __call__(self, name, globals=None, locals=None,
+		 fromlist=None, level=-1):
         """
         The import method itself.
         """
 
+	globals = globals or {}
+	locals = locals or {}
+	fromlist = fromlist or []
+
         self.begin()
         #try:
         # if not relative and not from applications:
         if not name.startswith(".") and level <= 0 \
                     and not name.startswith("applications.") \
@@ -306,6 +320,8 @@
 
 class _Web2pyDateTrackerImporter(_Web2pyImporter, _DateTrackerImporter):
     """
     Like _Web2pyImporter but using a _DateTrackerImporter.
     """
+
+