My goal is to find a difference in hours between now and some provided date\_time. I'm trying to do this this way:

```
pry(1)> dt1
#DateTime<2017-10-24 05:12:46.000000Z>

pry(2)> Ecto.DateTime.to_erl(dt1)
** (FunctionClauseError) no function clause matching in Ecto.DateTime.to_erl/1    

    The following arguments were given to Ecto.DateTime.to_erl/1:

        # 1
        #DateTime<2017-10-24 05:12:46.000000Z>

    Attempted function clauses (showing 1 out of 1):

        def to_erl(%Ecto.DateTime{year: year, month: month, day: day, hour: hour, min: min, sec: sec})

    (ecto) lib/ecto/date_time.ex:608: Ecto.DateTime.to_erl/1
    # ............

```

How to fix that? **Or is there a better way to achieve my goal?**

**Note** that I don't use timex and won't use it, neither any third-party library. Only ones built-in in Elixir/Erlang/Phoenix.