Add SEQUENCETYPE to handle the dict_keys type (#15953)

On python 3, there is a specific type for dict keys
instead of list, so previous tests based on Sequence didn't
not work anymore.

lib/ansible/module_utils/basic.py

@@ -123,6 +123,12 @@ except ImportError:
     Sequence = (list, tuple)
     Mapping = (dict,)
 
+try:
+    from collections.abc import KeysView
+    SEQUENCETYPE = (Sequence, KeysView)
+except:
+    SEQUENCETYPE = Sequence
+
 try:
     import json
     # Detect the python-json library which is incompatible
@@ -386,7 +392,7 @@ def return_values(obj):
                 # (still must deal with surrogateescape on python3)
                 yield obj.encode('utf-8')
         return
-    elif isinstance(obj, Sequence):
+    elif isinstance(obj, SEQUENCETYPE):
         for element in obj:
             for subelement in return_values(element):
                 yield subelement
@@ -422,7 +428,7 @@ def remove_values(value, no_log_strings):
             value = unicode(bytes_value, 'utf-8', errors='replace')
         else:
             value = bytes_value
-    elif isinstance(value, Sequence):
+    elif isinstance(value, SEQUENCETYPE):
         return [remove_values(elem, no_log_strings) for elem in value]
     elif isinstance(value, Mapping):
         return dict((k, remove_values(v, no_log_strings)) for k, v in value.items())