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' || +sampleActivity <= 0 || isNaN(+sampleActivity)){
        return false;
    }
    
    return Math.round(
      Math.log(MODERN_ACTIVITY / +sampleActivity) / HALF_LIFE_PERIOD
    );
  };
  