You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: mailman.rb
    path of file: ./repos/bugsnag-ruby/lib/bugsnag/integrations
    
    the code of the file until where you have to start completion: require 'mailman'

module Bugsnag
  ##
  # Extracts and appends mailman message information to error reports
  class Mailman

    FRAMEWORK_ATTRIBUTES = {
      :framework => "Mailman"
    }

    def initialize
      Bugsnag.configuration.internal_middleware.use(
    
    def call(mail)
      begin
        Bugsnag.configuration.set_request_data :mailman_msg, mail.to_s
        yield
      rescue Exception => ex
        Bugsnag.notify(ex, true) do |report|
          report.severity = "error"
          report.severity_reason = {
            :type => Bugsnag::Report::UNHANDLED_EXCEPTION_MIDDLEWARE,
            :attributes => FRAMEWORK_ATTRIBUTES
          }
        end
        raise
      ensure
        Bugsnag.configuration.clear_request_data
      end