Use def self.method to define singleton methods. ... # Also possible and convenient when you # have to define many singleton methods. class << self I w

Use def self.method to define singleton methods. ... # Also possible and convenient when you # have to define many singleton methods. class << self I would argue against using "class << self" especially when you have many singleton methods. If the class is large enough, it's easy to miss the "class << self" and incorrectly read a class method as an instance method.