docs: function(/* Array */ files) {
  
                      var preprocessor;
  
                      if (_.isEmpty(files)) {
                          return preprocessor;
                      }
  
                      // collect all the possible extensions
                      // and remove duplicates
                      files = _.chain(files).map(function (/* string */ file) {
  
                          var ext = path.extname(file).split('.');
  
                          return ext[ext.length - 1];
  
                      }).uniq().value();
  
                      preprocessor = _.find(Object.keys(plugin.preprocessors), function (/* String */ key) {
  
                          var value = plugin.preprocessors[key],
                              exts = value.split(/[,\s]+/),
  
                              matches = _.filter(files, function (/* String */ ext) {
                                  return exts.indexOf(ext) !== -1;
                              });
  
                          return !_.isEmpty(matches);
  
                      });
  
                      return preprocessor;
  
                  }