Add documentation for deprecated parts.

doc/deprecated.md

@@ -0,0 +1,47 @@
+# Deprecated
+
+## enissue.py
+### argparse
+Why: making mutually exclusive arguments or subcommands optional
+doesn't seem to work.
+- Use the Poikilos argparsebetter module such as from
+  <https://github.com/poikilos/argparsebetter> instead if such features
+  are necessary.
+```
+def main():
+    import argparse
+    parser = argparse.ArgumentParser(description='Process issues.')
+    subparsers = parser.add_subparsers()
+    # vParser = subparsers.add_parser('--verbose', aliases=['--debug'])
+    # vParser.add_argument('foo')
+    # qG = parser.add_mutually_exclusive_group(required=False)
+    # qG.add_argument('open', action='store_true')
+    # qG.add_argument('closed', action='store_false')
+    # ^ They have to be required, so see
+    #   <https://stackoverflow.com/questions/59773946/argparse-required-add-mutually-exclusive-group-parameters-list-as-optional>:
+    state_help = {}
+    for api_name, api in apis.items():
+        default_query = api.get('default_query')
+        default_query_state = default_query.get('state')
+        state_help[api_name] = default_query_state
+    '''
+    parser.add_argument('state', choices=['open', 'closed'],
+                        default="open",
+                        help=('Show open or closed issues only'
+                              ' (defaults are {}).'.format(state_help)))
+    '''
+    # ^ Makes it required so see
+    #   <https://stackoverflow.com/a/40324928/4541104>
+    #   on <https://stackoverflow.com/questions/40324356/python-argparse-choices-with-a-default-choice>
+
+    parser_list = subparsers.add_parser('open')
+    # parser_open.add_argument('open_type', default='all', const='all', nargs='?', choices=['all', 'servers', 'storage'])
+
+    parser_closed = subparsers.add_parser('closed')
+    # parser_closed.add_argument('closed_type', default='server', const='server', nargs='?', choices=['server', 'storage'])
+
+    # parser.print_help()
+    parser.parse_args(sys.argv)
+    print("open: {}".format(parser.get("open")))
+    sys.exit(0)
+```