Moar Updates

* Add support for `Sequence`, `Collection`, and `MutableSequence`
* Add support for container class with `Meta` config (#163)
* Fix for `NoneType`

dataclass_wizard/class_helper.py

@@ -303,10 +303,24 @@ def call_meta_initializer_if_needed(cls):
     """
     Calls the Meta initializer when the inner :class:`Meta` is sub-classed.
     """
+    # TODO add tests
+
+    cls_module = cls.__module__
+
+    # skip classes provided by this library
+    if cls_module.startswith('dataclass_wizard.'):
+        return
+
     cls_name = get_class_name(cls)
 
     if cls_name in META_INITIALIZER:
         META_INITIALIZER[cls_name](cls)
+    else:
+        for base in cls.__bases__:
+            base_cls_name = get_class_name(base)
+
+            if base_cls_name in META_INITIALIZER:
+                META_INITIALIZER[base_cls_name](cls)
 
 
 def get_meta(cls, base_cls=AbstractMeta):

dataclass_wizard/type_def.py

@@ -45,7 +45,6 @@
 from datetime import date, time, datetime
 from enum import Enum
 from os import PathLike
-from types import NoneType
 from typing import (
     Any, Type, TypeVar, Sequence, Mapping, List, Dict, DefaultDict, FrozenSet,
     Union, NamedTuple, Callable, AnyStr, TextIO, BinaryIO,
@@ -56,7 +55,15 @@
 )
 from uuid import UUID
 
-from .constants import PY311_OR_ABOVE, PY313_OR_ABOVE
+from .constants import PY310_OR_ABOVE, PY311_OR_ABOVE, PY313_OR_ABOVE
+
+
+# The class of the `None` singleton, cached for re-usability
+if PY310_OR_ABOVE:
+    # https://docs.python.org/3/library/types.html#types.NoneType
+    from types import NoneType
+else:
+    NoneType = type(None)
 
 # Type check for numeric types - needed because `bool` is technically
 # a Number.

dataclass_wizard/v1/loaders.py

@@ -1,6 +1,5 @@
 # TODO cleanup imports
 
-import types
 from base64 import decodebytes
 from collections import defaultdict, deque, namedtuple
 import collections.abc as abc
@@ -37,6 +36,7 @@
 from ..models import Extras, PatternedDT, TypeInfo
 from ..parsers import *
 from ..type_def import (
+    NoneType,
     ExplicitNull, FrozenKeys, DefFactory, NoneType, JSONObject,
     PyRequired, PyNotRequired, PyLiteralString,
     M, N, T, E, U, DD, LSQ, NT
@@ -60,7 +60,7 @@
 # returns the same object. We can provide a fast-path for these types in asdict and astuple.
 _SIMPLE_TYPES = (
     # Common JSON Serializable types
-    types.NoneType,
+    NoneType,
     bool,
     int,
     float,
@@ -718,6 +718,16 @@ def get_string_for_annotation(cls,
             # for the `cls` (base_type)
             load_hook = cls.load_to_dataclass
 
+        elif origin in (abc.Sequence, abc.MutableSequence, abc.Collection):
+            load_hook = cls.load_to_iterable
+            # desired (non-generic) origin type
+            origin = tuple if origin is abc.Sequence else list
+            # Get type arguments, e.g. `Sequence[int]` -> `int`
+            try:
+                args = get_args(type_ann)
+            except ValueError:
+                args = Any,
+
         else:
 
             # TODO everything should use `get_origin_v2`