You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: helpers.rb
    path of file: ./repos/chronomodel/spec/support/time_machine
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module ChronoTest
  module TimeMachine
    # This module contains helpers used throughout the
    # +ChronoModel::TimeMachine+ specs.
    
      def ts_eval(ctx = nil, &block)
        ret = (ctx || self).instance_eval(&block)
        (ctx || ret).tap do |obj|
          unless obj.methods.include?(:ts)
            obj.singleton_class.instance_eval do
              define_method(:ts) { @ts ||= [] }
            end
          end

          now = ChronoTest.connection.select_value('select now()::timestamp')
          case now
          when Time # Already parsed, thanks AR
            obj.ts.push(now)
          when String # ISO8601 Timestamp
            obj.ts.push(Time.parse("#{now}Z"))
          else
            raise "Don't know how to deal with #{now.inspect}"
          end