anchor.diff:  <1> Indicates that `date` values use a UTC offset of `+01:00`.
   <2> With a UTC offset of `+01:00`, {es} converts this date to
   `2014-12-31T23:00:00 UTC`.
  -<3> The `time_zone` parameter does not affect the `now` value.+<3> The `time_zone` parameter does not affect the `now` value.
  
positive.code: --
  Rounds down to the first millisecond.
  
  For example, `2014-11-18||/M` rounds down to `2014-11-01`, excluding
  the entire month.
  --
  
  
negative.code: --
  Rounds up to the lastest millisecond.
  
  For example, `2014-11-18||/M` rounds up to `2014-11-30T23:59:59.999`, excluding
  the entire month.
  --
  
  