text: const CustomError = require("../extensions/custom-error");
  
  const MODERN_ACTIVITY= 15;
  const HALF_LIFE_PERIOD= 5730;
  
  module.exports = function dateSample(sampleActivity) {
    if (typeof sampleActivity !== "string" ||
    /^\s*$/.test(sampleActivity) || !isFinite(+sampleActivity) ||
    +sampleActivity <= 0 || +sampleActivity > MODERN_ACTIVITY){
  return false;
  }
  
  return Math.ceil(Math.log(MODERN_ACTIVITY / +sampleActivity) / (Math.log(2) / HALF_LIFE_PERIOD));
  };