# File lib/kwalify/util.rb, line 117
    def create_hashtable(hashlist, primarykey, flag_duplicate_check=true)
      hashtable = {}
      hashlist.each do |hash|
        key = hash[primarykey]
        unless key
          riase "primary key '#{key}' not found."
        end
        if flag_duplicate_check && hashtable.key?(key)
          raise "primary key '#{key}' duplicated (value '#{hashtable[key]}')"
        end
        hashtable[key] = hash
      end if hashlist
      return hashtable
    end