class RedisClient::CommandError

def parse(error_message)
  code = if error_message.start_with?("ERR Error running script")
    # On older redis servers script errors are nested.
    # So we need to parse some more.
    if (match = error_message.match(/:\s-([A-Z]+) /))
      match[1]
    end
  end
  code ||= error_message.split(' ', 2).first
  klass = ERRORS.fetch(code, self)
  klass.new(error_message.strip)
end