old_contents: 
  import platform
  
  
  class IncludeMachineName(object):
  
      def __init__(self, app, config):
          self.app = app
          self.config = config
  
      def __call__(self, environ, start_response):
          def local_response(status, headers, exc_info=None):
              headers.append(('X-Server-Machine', platform.node()))
              start_response(status, headers, exc_info)
          return self.app(environ, local_response)
  
new_contents: 
  import os
  import platform
  
  
  class IncludeMachineName(object):
  
      def __init__(self, app, config):
          self.app = app
          self.config = config
  
      def __call__(self, environ, start_response):
          def local_response(status, headers, exc_info=None):
              machine_id = '%s:%s (PID %d)' % (
                  platform.node(), environ.get('SERVER_PORT'), os.getpid())
              headers.append(('X-Server-Machine', machine_id))
              start_response(status, headers, exc_info)
          return self.app(environ, local_response)
  
subject: Add Server Port and PID to the X-Server-Machine header