code: function (defaults, attr, custom) {
          var resolvedPath;
  
          if (defaults === undefined || defaults[attr] === undefined) {
              throw new Error('Missing Parameter', 'Expect a given defaults object');
          }
  
          if (attr === undefined) {
              throw new Error('Missing Parameter', 'Expect a given attribute');
          }
  
          if (custom === undefined || custom[attr] === undefined) {
              resolvedPath = path.resolve(defaults[attr]);
          } else {
              resolvedPath = path.resolve(custom[attr]);
          }
  
          return resolvedPath;
      }
docs: Retrieving a resolved path from defaults or custom options
  @param  {Object} defaults    Fallback options
  @param  {String} attr        Attribute to be resolved
  @param  {Object} custom      Custom options
  @return {String}             Resolved path from custom options or default if undefined