code: function populatePropertyFor (documents, next) {
      if (this._mongooseOptions.lean) {
        asArray(documents).forEach(function(doc) {
          paths.forEach(function(path) {
            try {
              const splitted = path.path.split('.');
              const key      = splitted.shift();
              const insert   = { values: path.enumValues };
              const value    = doc[key];
  
              insert.value = determineValue(splitted, value);
              doc[key]     = nest(splitted, insert);
            } catch (error) { return next(error); }
          });
        });
      }
  
      next();
    }
docs: Modify document enum (string) properties to an object, with (original) value and
  values (enumValues)