anchor.diff:  
       mapredSite = mkOption {
         default = {};
  +      type = types.attrsOf types.anything;
         example = literalExample ''
           {
             "mapreduce.map.cpu.vcores" = "1";
  
positive.code:   options.services.hadoop = {
      coreSite = mkOption {
        default = {};
        example = literalExample ''
          {
            "fs.defaultFS" = "hdfs://localhost";
  
negative.code: 
      yarnSite = mkOption {
        default = {};
        type = types.attrsOf types.anything;
        example = literalExample ''
          {
            "yarn.resourcemanager.ha.id" = "resourcemanager1";
  