NullObject VS GuardClause (http://joejames.io/post/an-alternative-for-guard-clauses-that-do-type-checking)

nil_check.rb

# Example of a guard clause performing a nil check
class BlahSpeaker
  has_one :audience
  
  def speak
    return if audience.nil?
    audience.address('blah ' * 100)
  end
end

null_object.rb

# Example of `NullObject` pattern
class BlahSpeaker
  has_one :audience
  
  NullAudience = Class.new do
    def address(words); end
  end
  
  def speak
    (audience || NullAudience.new).address('blah ' * 100)
  end
end