Update README.md

Author: stannielson

README.md

@@ -3,14 +3,15 @@
 
 When other approaches are impractical, the `disinheritance` module may be a viable alternative. The `disinherit` decorator object automatically overrides unwanted inherited methods and attributes and prevents their use in subclass instances, except where specified as exemptions. Features of `disinherit` include:
 
-* Exemptions can be one or more type methods/attributes or even entire types in the subclass MRO (though exemptions are managed internally by type/containing type and declaration order)
+* Exemptions can be one or more type methods or even entire types in the subclass MRO (though exemptions are managed internally by type/containing type and declaration order)
 * Exemptions can be from anywhere in the MRO and will be applied to the subclass as overrides (unless already overriden in the subclass)
 * `dir()` call on a subclass instance will not include disinherited methods/attributes
 * Attempts at attribute retrieval of disinherited methods/attributes from an instance produce attribute errors
 * `help()` call on a subclass type will show disinherited methods/attributes as not implemented (i.e., as the `NotImplemented` singleton)
 * Invalid exemptions (i.e., types and type methods/attributes not in the MRO) are silently ignored
 * Subclass `__dir__` and `__getattribute__` methods are wrapped to both maintain original functionality and account for disinherited methods/attributes
 * Exemptions are explicitly specified using an `exempt` keyword argument for the sake of clarity and deliberate use in style
+* _Note: type attributes cannot be directly referenced for exemptions where an attribute does not back-reference the containing type_
 
 ## Example:
 ```