Make SettingsDict a UserDict

This allows us to set arbitrary attributes and then later retrieve them
from the frame locals.

Author: orlnub123

class_settings/env.py

@@ -23,10 +23,13 @@ def __init__(self):
                 self.parser(parser)
 
     def __call__(self, name=None, *, prefix=missing, default=missing, optional=False):
+        from .settings import SettingsDict
+
         frame = sys._getframe(1)
         while frame is not None:
-            options = frame.f_locals.get("__options__")
-            if isinstance(options, Options):
+            f_locals = frame.f_locals
+            if isinstance(f_locals, SettingsDict):
+                options = f_locals.options
                 break
             frame = frame.f_back
         else:

class_settings/settings.py

@@ -1,6 +1,7 @@
 import __future__
 
 import ast
+import collections
 import copy
 import inspect
 import sys
@@ -13,9 +14,10 @@
 from .options import Options
 
 
-class SettingsDict(dict):
+class SettingsDict(collections.UserDict):
     def __init__(self, *, options, bases):
-        super().__init__(__options__=options)
+        super().__init__()
+        self.options = options
         if options.inject_settings:
             to_inject = {}
             for base in reversed(bases):
@@ -75,13 +77,10 @@ def __prepare__(name, bases):
         return SettingsDict(options=Options(meta), bases=bases)
 
     def __new__(meta, name, bases, namespace):
-        options = namespace.pop("__options__", None)
-        if not isinstance(options, Options):
-            raise AttributeError("__options__ cannot be overwritten")
         if "Meta" in namespace and not isinstance(namespace["Meta"], type):
             raise TypeError("{}.Meta has to be a class".format(name))
-        namespace["_options"] = options
-        return super().__new__(meta, name, bases, namespace)
+        namespace["_options"] = namespace.options
+        return super().__new__(meta, name, bases, namespace.data)
 
     def __dir__(cls):
         default_settings = cls._options.default_settings