polish package a bit

.gitignore

@@ -0,0 +1,5 @@
+.cache
+*.pyc
+__pycache__
+build/
+dist/

LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2015 Matthias Bussonnier
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

flit.ini

@@ -0,0 +1,8 @@
+[metadata]
+module = undefined
+author = Matthias Bussonnier
+author-email = [email protected]
+home-page = https://github.com/Carreau/undefined
+classifiers = License :: OSI Approved :: MIT License
+requires-python = >=3.4
+

undefined/__init__.py

@@ -6,4 +6,30 @@
 
 __version__ = '0.0.1'
 
-
+import sys
+import types
+
+class Undefined(types.ModuleType):
+
+
+    @property
+    def Undefined(self):
+        return self
+
+    def __call__(self, value):
+        return value is self
+
+    def __repr__(self):
+        return self.__class__.__name__
+
+    __str__ = __repr__
+
+
+Undefined.__name__ = 'Undefined'
+Undefined = Undefined('undefined')
+
+if sys.modules[__name__] is Undefined:
+    print('doing nothing')
+    pass
+else:
+   sys.modules[__name__] = Undefined

undefined/tests/test_undefined.py

@@ -0,0 +1,7 @@
+import undefined as ud
+from  undefined import Undefined as uc
+
+
+def test_undefined():
+    assert ud is uc
+