python-3.6.zip added from Github

README.cosmo contains the necessary links.

third_party/python/PC/testpy.py

@@ -0,0 +1,30 @@
+import sys
+
+# This is a test module for Python.  It looks in the standard
+# places for various *.py files.  If these are moved, you must
+# change this module too.
+
+try:
+    import os
+except:
+    print("""Could not import the standard "os" module.
+  Please check your PYTHONPATH environment variable.""")
+    sys.exit(1)
+
+try:
+    import symbol
+except:
+    print("""Could not import the standard "symbol" module.  If this is
+  a PC, you should add the dos_8x3 directory to your PYTHONPATH.""")
+    sys.exit(1)
+
+for dir in sys.path:
+    file = os.path.join(dir, "os.py")
+    if os.path.isfile(file):
+        test = os.path.join(dir, "test")
+        if os.path.isdir(test):
+            # Add the "test" directory to PYTHONPATH.
+            sys.path = sys.path + [test]
+
+import libregrtest # Standard Python tester.
+libregrtest.main()