def from_superclass(m, default = nil)
      return default if superclass == Cleanroom
      superclass.respond_to?(m) ? superclass.send(m) : default
    end
def from_superclass(m, default = nil)
      return default if superclass == Cleanroom
      superclass.respond_to?(m) ? superclass.send(m) : default
    end
Get the value from the superclass, if it responds, otherwise return
 +default+. Since class instance variables are **not** inherited upon
 subclassing, this is a required check to ensure subclasses inherit
 exposed DSL methods.

 @param [Symbol] m
   the name of the method to find
 @param [Object] default
   the default value to return if not found