An object of class MethodExtension when added to a Method
creates a ExtendedMethod.
namea short name identifier. Must be alphanumeric.
labela longer, human readable label that can have other characters such as spaces, hyphens, etc.
method_extensiona function with arguments "model", "draw", "out", and
"base_method". This will become the function extended_method
in the ExtendedMethod object that is created.
This class inherits from the Component class.