whole_func_string: function sum(arr, prop){
    return arr.reduce(function(sum, obj){
      return sum + obj.stats[prop];
    }, 0);
  }
func_code_string: function sum(arr, prop){
    return arr.reduce(function(sum, obj){
      return sum + obj.stats[prop];
    }, 0);
  }
func_documentation_string: Return sum of each `prop` in `arr`.
  
  @param {Array} arr
  @param {String} prop
  @return {Number}
  @api private