updated contents from Atlas repo

decorators/local_demo.py

@@ -0,0 +1,63 @@
+"""
+>>> f1(3)
+>>> b = 8
+>>> f1(3)
+a = 3
+b = 8
+>>> f2(3)
+Traceback (most recent call last):
+  ...
+UnboundLocalError: local variable 'b' referenced before assignment
+>>> f3(3)
+a = 3
+b = 7
+b = 6
+>>> b = -5
+>>> ff = f4()
+>>> ff(3)
+a = 3
+b = 11
+b = 6
+>>> print('b =', b)
+b = -5
+"""
+
+def f1(a):
+    print('a =', a)
+    print('b =', b)
+
+def f2(a):
+    print('a =', a)
+    print('b =', b)
+    b = a * 10
+    print('b =', b)
+
+def f3(a):
+    global b
+    print('a =', a)
+    print('b =', b)
+    b = a * 10
+    print('b =', b)
+
+def f3b(a):
+    nonlocal b
+    print('a =', a)
+    print('b =', b)
+    b = a * 10
+    print('b =', b)
+
+def f4():
+    b = 11
+    def f5(a):
+        nonlocal b
+        print('a =', a)
+        print('b =', b)
+        b = a * 2
+        print('b =', b)
+    return f5
+
+import doctest
+doctest.testmod(optionflags=doctest.ELLIPSIS | doctest.NORMALIZE_WHITESPACE)
+
+
+