just playing around with ruby ( experimenting ). hopefully someone can help anyways... everytime I do this code

class MYLIB
def s
self.to_s
end

def i
self.to_i
end

def f
self.to_f
end
end

class String < MYLIB

end

class Integer < MYLIB

end
I keep getting this error

classes.rb:15: superclass mismatch for class String (TypeError)
line 15 being this code

class String < MYLIB