Migrate most uses of if type() to if isinstance()

Also convert those checks to use abcs instead of dict and list.

Make a sentinel class for strategies to report when they've reache the end

contrib/inventory/ssh_config.py

@@ -43,13 +43,16 @@
 import argparse
 import os.path
 import sys
-import paramiko
+from collections import MutableSequence
 
 try:
     import json
 except ImportError:
     import simplejson as json
 
+import paramiko
+
+
 SSH_CONF = '~/.ssh/config'
 
 _key = 'ssh_config'
@@ -68,7 +71,7 @@ def get_config():
         cfg.parse(f)
         ret_dict = {}
         for d in cfg._config:
-            if type(d['host']) is list:
+            if isinstance(d['host'], MutableSequence):
                 alias = d['host'][0]
             else:
                 alias = d['host']
@@ -93,7 +96,7 @@ def print_list():
                 # If the attribute is a list, just take the first element.
                 # Private key is returned in a list for some reason.
                 attr = attributes[ssh_opt]
-                if type(attr) is list:
+                if isinstance(attr, MutableSequence):
                     attr = attr[0]
                 tmp_dict[ans_opt] = attr
         if tmp_dict: