class DoSomething
	def self.build(dep:)
		->(user:) {
			self.new(dep: dep, user: user).call
		}
	end

	def initialize(dep:, user:)
		@dep = dep
		@user = user
	end

	def call
		{
			current: report[:current],
			previous: report[:previous],
		}
	end

	private

	# We should be able to memoize an instance variable
	# without worrying about the side effects of this
	def report
		@report ||= expensive_computation(@user)
	end

	def expensive_computation(user)
		{
			current: "current for " + user,
			previous: "previous for " + user,
		}
	end
end

# You can build an interactor injecting dependecies
interactor = DoSomething.build(dep: {})

# And call it with different parameters
puts interactor.call(user: "Sam")
puts interactor.call(user: "Tess")

# Or you can do everything in one
 puts DoSomething.new(dep: {}, user: "Sally").call