class Slack::Web::Faraday::Response::RaiseError

def on_complete(env)
  raise Slack::Web::Api::Errors::TooManyRequestsError, env.response if env.status == 429
  return unless (body = env.body) && !body['ok']
  error_message =
    body['error'] || body['errors'].map { |message| message['error'] }.join(',')
  raise Slack::Web::Api::Errors::SlackError.new(error_message, env.response)
end