change.rb

class Smartphone::Contract::Change < BaseInteraction  
  def call
    return unless valid_interaction?  
    persist_models!
    change_certificate
  end
  
  def valid_interaction?
    not_suspended?
      && invoices_settled?
      && previous_attributes_valid?
      && new_attributes_valid?
      && suspended_subscription.success?
  end
    
  def not_suspended?
    # 
  end
  
  def invoices_settled?
    #
  end
  
  def previous_attributes_valid?
    #
  end
  
  def new_attributes_valid?
    #
  end
  
  def suspended_subscription
    #
  end
  
  def change_certificate
    #
  end
  
  def persist_models!
    #
  end
end