diff --git a/src/Nirum/Targets/Python.hs b/src/Nirum/Targets/Python.hs
index 5bf6abf..d0fd5e9 100644
--- a/src/Nirum/Targets/Python.hs
+++ b/src/Nirum/Targets/Python.hs
@@ -258,6 +258,17 @@ renameMP Python { renames = table } = renameModulePath table
 thd3 :: (a, b, c) -> c
 thd3 (_, _, v) = v
 
+mangleVar :: Code -> T.Text -> Code
+mangleVar expr arbitrarySideName = T.concat
+    [ "__nirum_"
+    , (`T.map` expr) $ \ c -> if 'A' <= c && c <= 'Z' ||
+                                 'a' <= c && c <= 'z' || c == '_'
+                              then c else '_'
+    , "__"
+    , arbitrarySideName
+    , "__"
+    ]
+
 -- | The set of Python reserved keywords.
 -- See also: https://docs.python.org/3/reference/lexical_analysis.html#keywords
 keywords :: S.Set T.Text
@@ -648,14 +659,25 @@ compileSerializer' mod' (OptionModifier typeExpr) pythonVar =
 compileSerializer' mod' (SetModifier typeExpr) pythonVar =
     compileSerializer' mod' (ListModifier typeExpr) pythonVar
 compileSerializer' mod' (ListModifier typeExpr) pythonVar =
-    [qq|[($serializer) for __{pythonVar}__elem__ in ($pythonVar)]|]
+    [qq|list(($serializer) for $elemVar in ($pythonVar))|]
   where
+    elemVar :: Code
+    elemVar = mangleVar pythonVar "elem"
     serializer :: Code
-    serializer = compileSerializer' mod' typeExpr [qq|__{pythonVar}__elem__|]
+    serializer = compileSerializer' mod' typeExpr elemVar
 compileSerializer' mod' (MapModifier kt vt) pythonVar =
-    [qq|\{({compileSerializer' mod' kt $ T.concat ["__", pythonVar, "__k__"]}):
-          ({compileSerializer' mod' vt $ T.concat ["__", pythonVar, "__v__"]})
-         for __{pythonVar}__k__, __{pythonVar}__v__ in ($pythonVar).items()\}|]
+    [qq|list(
+        \{
+            'key': ({compileSerializer' mod' kt kVar}),
+            'value': ({compileSerializer' mod' vt vVar}),
+        \}
+        for $kVar, $vVar in ($pythonVar).items()
+    )|]
+  where
+    kVar :: Code
+    kVar = mangleVar pythonVar "key"
+    vVar :: Code
+    vVar = mangleVar pythonVar "value"
 compileSerializer' mod' (TypeIdentifier typeId) pythonVar =
     case lookupType typeId mod' of
         Missing -> "None"  -- must never happen
diff --git a/test/nirum_fixture/fixture/foo.nrm b/test/nirum_fixture/fixture/foo.nrm
index 9807636..a673869 100644
--- a/test/nirum_fixture/fixture/foo.nrm
+++ b/test/nirum_fixture/fixture/foo.nrm
@@ -129,3 +129,7 @@ service sample-service (
     sample-method (animal a, product b/bb, gender c, way d/dd,
                    uuid e, binary f/ff, bigint g, text h/hh),
 );
+
+record record-with-map (
+    {text: text} text-to-text,
+);
diff --git a/test/python/primitive_test.py b/test/python/primitive_test.py
index 40ebd8a..638e5dd 100644
--- a/test/python/primitive_test.py
+++ b/test/python/primitive_test.py
@@ -5,14 +5,16 @@
 from nirum.service import Service
 from six import PY3
 
-from fixture.foo import (CultureAgnosticName, Dog,
+from fixture.foo import (Album, CultureAgnosticName, Dog,
                          EastAsianName, EvaChar,
                          FloatUnbox, Gender, ImportedTypeUnbox, Irum,
                          Line, MixedName, Mro, Music, NoMro, NullService,
+                         Person, People,
                          Point1, Point2, Point3d, Pop, PingService, Product,
-                         RecordWithOptionalRecordField,
+                         RecordWithMap, RecordWithOptionalRecordField,
                          ReservedKeywordEnum, ReservedKeywordUnion,
-                         Rnb, RpcError, Run, Status, Stop, Way, WesternName)
+                         Rnb, RpcError, Run, Song, Status, Stop, Way,
+                         WesternName)
 from fixture.foo.bar import PathUnbox, IntUnbox, Point
 from fixture.qux import Path, Name
 
@@ -351,3 +353,43 @@ def test_nirum_tag_classes():
         Status.Tag.run: Run,
         Status.Tag.stop: Stop,
     }
+
+
+def test_list_serializer():
+    album = Album(name=u'Album title', tracks=[Song(name=u'Song title')])
+    assert album.__nirum_serialize__() == {
+        '_type': 'album',
+        'name': u'Album title',
+        'tracks': [
+            {'_type': 'song', 'name': u'Song title'},
+        ],
+    }
+
+
+def test_set_serializer():
+    people = People(people={
+        Person(first_name=Name(u'First'), last_name=Name(u'Last')),
+    })
+    assert people.__nirum_serialize__() == {
+        '_type': 'people',
+        'people': [
+            {
+                '_type': 'person',
+                'first_name': u'First',
+                'last_name': u'Last',
+            },
+        ]
+    }
+
+
+def test_map_serializer():
+    record = RecordWithMap(text_to_text={u'key': u'value'})
+    assert record.__nirum_serialize__() == {
+        '_type': 'record_with_map',
+        'text_to_text': [
+            {
+                'key': u'key',
+                'value': u'value',
+            },
+        ],
+    }