Merge pull request #77 from davidbrochart/fix_win3.6

Fix for windows/python<3.7

Author: MSeal

nbclient/__init__.py

@@ -1,2 +1,17 @@
+import sys
+import subprocess
 from .client import NotebookClient, execute  # noqa: F401
 from ._version import version as __version__  # noqa: F401
+
+
+def _cleanup():
+    pass
+
+
+# patch subprocess on Windows for python<3.7
+# see https://bugs.python.org/issue37380
+# the fix for python3.7: https://github.com/python/cpython/pull/15706/files
+if sys.platform == 'win32':
+    if sys.version_info < (3, 7):
+        subprocess._cleanup = _cleanup
+        subprocess._active = None