text: const MODERN_ACTIVITY= 15; 
  const HALF_LIFE_PERIOD= 5730;
  
  module.exports = function dateSample(sampleActivity) {
   const sampleActivityn = parseFloat(sampleActivity, 10);
    
    if (!sampleActivity 
      || !isFinite(sampleActivityn)
      || typeof sampleActivity !== 'string' 
      || (sampleActivityn >= MODERN_ACTIVITY)
      || (sampleActivityn <= 0)
      ) return false;
    
      const k = 0.693 / HALF_LIFE_PERIOD;
      return Math.ceil(Math.log(MODERN_ACTIVITY / sampleActivityn) / k);
            
      
  
  };
  