Iterable support

flatten_json.py

@@ -15,6 +15,7 @@
 import copy
 import re
 from math import isnan
+from collections.abc import Iterable
 
 
 def _construct_key(previous_key, separator, new_key):
@@ -72,7 +73,7 @@ def _flatten(object_, key):
                     _flatten(object_[object_key], _construct_key(key,
                                                                  separator,
                                                                  object_key))
-        elif isinstance(object_, (list, set, tuple)):
+        elif isinstance(object_, Iterable):
             for index, item in enumerate(object_):
                 _flatten(item, _construct_key(key, separator, index))
         # Anything left take as is

test_flatten.py

@@ -2171,6 +2171,19 @@ def test_flatten_ignore_keys(self):
         actual = flatten(dic, root_keys_to_ignore={'b', 'c'})
         self.assertEqual(actual, expected)
 
+    def test_flatten_custom_iterable(self):
+        class customIter:
+            def __init__(self, lst):
+                self.val = lst
+
+            def __iter__(self):
+                return self.val.__iter__()
+
+        elst = {'a': customIter([0, 1, 2])}
+        expected = {'a_0': 0, 'a_1': 1, 'a_2': 2}
+        actual = flatten(elst)
+        self.assertEqual(actual, expected)
+
     def test_command_line(self):
         input_stream = StringIO(u'{"a": {"b": 1}}')
         output_stream = StringIO()