Error to read .HistoricItem.getState() on null

Setup, Configuration and Use Beginners
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6

I’m sorry, I just didn’t get it right away.
Syntax:

if (Total_act.historicState(parse(Total_String)) != null) {
    Cht_at7 = Total_act.historicState(parse(Total_String)).state as Number
}

it works! Thanks!