@@ -2783,12 +2783,13 @@ class so far, an alias named ``get_alias`` will be defined; the same will
27832783 exception will be raised.
27842784
27852785 The alias map is stored as the ``_alias_map`` attribute on the class and
2786- can be used by `~.normalize_kwargs`.
2786+ can be used by `~.normalize_kwargs` (which assumes that higher priority
2787+ aliases come last).
27872788 """
27882789if cls is None :
27892790return functools .partial (_define_aliases ,alias_d )
27902791
2791- def make_alias (name ):#Enfore a closure over *name*.
2792+ def make_alias (name ):#Enforce a closure over *name*.
27922793def method (self ,* args ,** kwargs ):
27932794return getattr (self ,name )(* args ,** kwargs )
27942795return method
@@ -2804,7 +2805,11 @@ def method(self, *args, **kwargs):
28042805method .__doc__ = "alias for `{}`" .format (prefix + prop )
28052806setattr (cls ,prefix + alias ,method )
28062807if not exists :
2807- raise ValueError ("property {} does not exist" .format (prop ))
2808+ raise ValueError (
2809+ "Neither getter nor setter exists for {!r}" .format (prop ))
28082810
2811+ if hasattr (cls ,"_alias_map" ):
2812+ # Need to decide on conflict resolution policy.
2813+ raise NotImplementedError ("Parent class already defines aliases" )
28092814cls ._alias_map = alias_d
28102815return cls