How to call another method from a self method with ruby?

class Product < ApplicationRecord
  def self.method1(param1)
    # Here I want to call method2 with a parameter
    method2(param2)
  end

  def self.method2(param2)
    # Do something
  end
end

Explanation: first one is a class method, the latter was an instance method. Class methods don't need a receiver (an object who call them), instance methods need it. So, you can't call an instance method from a class method because you don't know if you have a receiver (an instanciated object who call it).

It does not work because method2 is not defined for Product object.

method2 is an instance method, and can be called only on the instance of Product class.