ruby method overridding

class Foo
  def bar
    puts "There can be only one?"
  end
end

f = Foo.new

orig_method = f.method(:bar)

def f.bar
  puts "No, I'm bar"
end

new_method = f.method(:bar)

orig_method.call
new_method.call

which_one = f.method(:bar)
which_one.call