code: def get_identities(self, item):
          
          identities = []
  
          if 'data' not in item:
              return identities
          if 'revisions' not in item['data']:
              return identities
  
          revisions = item['data']['revisions']
  
          for revision in revisions:
              user = self.get_sh_identity(revision)
              yield user
docs: Return the identities from an item