Implement dict() style constructor.

Already supported dict() and dict(mapping).
Now supports dict(itemsequence) and
Just van Rossum's new syntax for dict(keywordargs).

Also, added related unittests.

The docs already promise dict-like behavior
so no update is needed there.

Lib/UserDict.py

 """A more or less complete user-defined wrapper around dictionary objects."""
 
 class UserDict:
-    def __init__(self, dict=None):
-        self.data = {}
-        if dict is not None: self.update(dict)
+    def __init__(self, dict=None, **kwargs):
+        self.data = kwargs              # defaults to {}
+        if dict is not None:
+            if hasattr(dict,'keys'):    # handle mapping (possibly a UserDict)
+                self.update(dict)
+            else:                       # handle sequence
+                DICT = type({})  # because builtin dict is locally overridden
+                self.data.update(DICT(dict))
     def __repr__(self): return repr(self.data)
     def __cmp__(self, dict):
         if isinstance(dict, UserDict):

Lib/test/test_userdict.py

@@ -19,6 +19,9 @@ uu0 = UserDict(u0)
 uu1 = UserDict(u1)
 uu2 = UserDict(u2)
 
+verify(UserDict(one=1, two=2) == d2)            # keyword arg constructor
+verify(UserDict([('one',1), ('two',2)]) == d2)  # item sequence constructor
+
 # Test __repr__
 
 verify(str(u0) == str(d0))