How to convert DateTime to Time reliably (monkey patching)

date.rb

class Date
  def to_gm_time
    to_real_time(new_offset, :gm)
  end

  def to_local_time
    to_real_time(new_offset(DateTime.now.offset-offset), :local)
  end

  def to_real_time(dest=new_offset, method=:utc)   # don't use to_time because it could be overridden by ActiveSupport if it's required after this file
    usec = (dest.sec_fraction * 10**6).to_i
    Time.send(method, dest.year, dest.month, dest.day, dest.hour, dest.min,
              dest.sec, usec)
  end
end