client.rb

class Client
  attr_reader :item
  
  def initialize(item)
    @item = item  
  end
  
  def calculate_something
    80 * 20
  end
  
  
  # item it's object that have some different 
  # set of methods: [created_at, balance, goods], [one, two, three]
  # How we can execute methods from item when it executes on Client instance variable
end