module ActiveSupport::Tryable

def try(*a, &b)
  try!(*a, &b) if a.empty? || respond_to?(a.first)
end

def try!(*a, &b)
  if a.empty? && block_given?
    if b.arity == 0
      instance_eval(&b)
    else
      yield self
    end
  else
    public_send(*a, &b)
  end
end