1. A non-transitory electronic-device readable storage medium storing one or more instructions for: accepting a specification of one or more features of an accessed class, the accessed class: having one or more specified features, and having one or more non-specified features; accepting a specification of an accessing class to be granted access to the one or more specified features of the object-oriented class; and allowing the accessing class access to the one or more specified features of the accessed class while preventing the specified accessing class from accessing the one or more non-specified features of the accessed class, or preventing the specified accessing class from accessing the one or more specified features of the accessed class while allowing the specified accessing class to access one or more non-specified features of the accessed class.