Add fallback decorators -- otherwise

generic/multidispatch.py

@@ -106,6 +106,13 @@ class FunctionDispatcher(object):
             return self
         return register_rule
 
+    @property
+    def otherwise(self):
+        def register_rule(func):
+            self.register_rule(func, [object]*self.params_arity)
+            return self
+        return register_rule
+
     def override(self, *argtypes):
         def override_rule(func):
             self.override_rule(func, *argtypes)
@@ -158,6 +165,13 @@ class MethodDispatcher(FunctionDispatcher):
 
     override = when
 
+    @property
+    def otherwise(self):
+        def make_declaration(func):
+            self.register_unbound_rule(func, [object]*self.params_arity)
+            return self
+        return make_declaration
+
 
 def arity(argspec):
     """ Determinal positional arity of argspec."""