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' || arguments.length == 0 || sampleActivity > 15 || sampleActivity <= 0 || isNaN (sampleActivity) ) {
      return false;
    }
  
    let k = 0.693 / HALF_LIFE_PERIOD;
    let t = Math.ceil(Math.log(MODERN_ACTIVITY / sampleActivity) / k);
    return t;
  };
  