class ActiveSupport::HashWithIndifferentAccess

def update_with_single_argument(other_hash, block)
  if other_hash.is_a? HashWithIndifferentAccess
    regular_update(other_hash, &block)
  else
    other_hash.to_hash.each_pair do |key, value|
      if block && key?(key)
        value = block.call(convert_key(key), self[key], value)
      end
      regular_writer(convert_key(key), convert_value(value))
    end
  end
end