Patch for argparse.py before Python 3.7

argparse.patch

--- /home/ec2-user/anaconda3/lib/python3.6/argparse.py  2018-04-29 16:18:42.000000000 +0000
+++ argparse.py 2018-08-13 02:30:36.317112960 +0000
@@ -1064,6 +1064,7 @@
                  prog,
                  parser_class,
                  dest=SUPPRESS,
+                 required=False,
                  help=None,
                  metavar=None):

@@ -1077,6 +1078,7 @@
             dest=dest,
             nargs=PARSER,
             choices=self._name_parser_map,
+            required=required,
             help=help,
             metavar=metavar)