def symbolize(hash)
      {}.tap do |h|
        hash.each { |key, value| h[key.to_sym] = map_value_symbol(value) }
      end
    end
def symbolize(hash)
      {}.tap do |h|
        hash.each { |key, value| h[key.to_sym] = map_value_symbol(value) }
      end
    end
This method is called to convert all the keys of a hash into symbols to allow consistent usage of hashes within your Ruby application.