# File lib/mocha/mock.rb, line 141
    def stubs(method_name_or_hash, backtrace = nil)
      iterator = ArgumentIterator.new(method_name_or_hash)
      iterator.each do |*args|
        method_name = args.shift
        ensure_method_not_already_defined(method_name)
        expectation = Expectation.new(self, method_name, backtrace)
        expectation.at_least(0)
        expectation.returns(args.shift) unless args.empty?
        @expectations.add(expectation)
      end
    end