fix isort, pypy

Author: matthiasdiener

pytools/debug.py

@@ -1,7 +1,7 @@
 import sys
+from typing import Collection, List, Optional, Set
 
 from pytools import memoize
-from typing import List, Set, Optional, Collection
 
 
 # {{{ debug files -------------------------------------------------------------

test/test_debug.py

@@ -20,7 +20,12 @@
 THE SOFTWARE.
 """
 
+import sys
 
+import pytest
+
+
+@pytest.mark.skipif(hasattr(sys, "pypy_version_info"), reason="not support on PYPY")
 def test_get_object_cycles():
     from pytools.debug import get_object_cycles
     assert len(get_object_cycles([])) == 0