python-3.6.zip added from Github

README.cosmo contains the necessary links.

third_party/python/Lib/test/tf_inherit_check.py

@@ -0,0 +1,27 @@
+# Helper script for test_tempfile.py.  argv[2] is the number of a file
+# descriptor which should _not_ be open.  Check this by attempting to
+# write to it -- if we succeed, something is wrong.
+
+import sys
+import os
+from test.support import SuppressCrashReport
+
+with SuppressCrashReport():
+    verbose = (sys.argv[1] == 'v')
+    try:
+        fd = int(sys.argv[2])
+
+        try:
+            os.write(fd, b"blat")
+        except OSError:
+            # Success -- could not write to fd.
+            sys.exit(0)
+        else:
+            if verbose:
+                sys.stderr.write("fd %d is open in child" % fd)
+            sys.exit(1)
+
+    except Exception:
+        if verbose:
+            raise
+        sys.exit(1)