code: def normalize_attachment(attachment):
          ''' Convert attachment metadata from es to archivant format
  
              This function makes side effect on input attachment
          '''
          res = dict()
          res['type'] = 'attachment'
          res['id'] = attachment['id']
          del(attachment['id'])
          res['url'] = attachment['url']
          del(attachment['url'])
          res['metadata'] = attachment
          return ref normalize_attachment(attachment):
          ''' Convert attachment metadata from es to archivant format
  
              This function makes side effect on input attachment
          '''
          res = dict()
          res['type'] = 'attachment'
          res['id'] = attachment['id']
          del(attachment['id'])
          res['url'] = attachment['url']
          del(attachment['url'])
          res['metadata'] = attachment
          return res
docs: Convert attachment metadata from es to archivant format
  
              This function makes side effect on input attachment