You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: random_partitioner.rb
    path of file: ./repos/roma/lib/roma/routing
    
    the code of the file until where you have to start completion: module Roma
  module Routing
    module RandomPartitioner
      def exclude_nodes(ap_str, rep_host)
        exclude_nodes = nodes
        if rep_host
          exclude_nodes = [ap_str]
       
    
      def select_vn_for_balance(exclude_nodes, _rep_host)
        short_idx = {}
        idx = {}
        @rd.v_idx.each_pair do |vn, nids|
          unless list_include?(nids, exclude_nodes)
            idx[vn] = nids
            short_idx[vn] = nids if nids.length < @rd.rn
          end
        end