code: def _filter_unique_identities(uidentities, matcher):
      
      filtered = []
      no_filtered = []
      uuids = {}
  
      for uidentity in uidentities:
          n = len(filtered)
          filtered += matcher.filter(uidentity)
  
          if len(filtered) > n:
              uuids[uidentity.uuid] = uidentity
          else:
              no_filtered.append([uidentity])
  
      return filtered, no_filtered, uuids
docs: Filter a set of unique identities.
  
      This function will use the `matcher` to generate a list
      of `FilteredIdentity` objects. It will return a tuple
      with the list of filtered objects, the unique identities
      not filtered and a table mapping uuids with unique
      identities.