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') && parseInt(sampleActivity)>0 && parseInt(sampleActivity) < 15  ) {
    
      let result = Math.log(MODERN_ACTIVITY/parseFloat(sampleActivity))/ (0.693/HALF_LIFE_PERIOD)
  
     return Math.ceil(result)
  
   }else{
     return false;
   }
  
  };