Método de exclusão de rubi
# How to delete instance methods
# define an empty class
class Foo; end
# show all instance methods of Foo defined directyl on it
p Foo.instance_methods(false) #=> []
# add the `bar` method
class Foo
def bar
puts "I'm Foo#bar!"
end
end
p Foo.instance_methods(false) #=> [:bar]
Foo.new.bar #=> I'm Foo#bar!
# delete the method
Foo.undef_method(:bar)
p Foo.instance_methods(false) #=> []
Foo.new.bar #=> undefined method `bar' for #<Foo:0x0000000106c9ef80> (NoMethodError)
Mateusz Drewniak