tests: Really fix import.

tests/basics/class_store_class.py

@@ -2,6 +2,9 @@
 # There was a bug in MicroPython that under some conditions class stored
 # in instance attribute later was returned "bound" as if it was a method,
 # which caused class constructor to receive extra argument.
+try:
+    from collections import namedtuple
+except ImportError:
     from _collections import namedtuple
 
 _DefragResultBase = namedtuple('DefragResult', 'foo bar')