code for an video about define_method: https://youtu.be/I0itVuoprAY

define_method.rb

class ModelBase
  def self.enum(**kwargs)
    kwargs.each do |key, values|
      define_method("#{key}=") do |v|
        if values.include?(v)
          instance_variable_set("@#{key}", v)
        else
          raise "Not a valid status: #{v}"
        end
      end
      define_method(key) do
        instance_variable_get("@#{key}")
      end
      values.each do |v|
        define_method("#{v}!") do
          self.send("#{key}=", v)
        end

        define_method("#{v}?") do
          self.send(key) == v
        end
      end
    end
  end
end
class Event < ModelBase
  enum status: [:pending, :success, :failed]
end
event = Event.new
event.pending!
puts event.success?
puts event.pending?