code: def cover(
      self, pairs: TrainingExamples, index_predicates: bool = True
  ) -> Cover:
      predicate_cover = {}
      if index_predicates:
          predicates = self.blocker.predicates
      else:
          predicates = [
              pred
              for pred in self.blocker.predicates
              if not hasattr(pred, "index")
          ]
  
      for predicate in predicates:
          try:
              coverage = frozenset(
                  i
                  for i, (record_1, record_2) in enumerate(pairs)
                  if not predicate(record_1).isdisjoint(
                      predicate(record_2, target=True)
                  )
              )
          except AttributeError:
              warn(
                  f"the predicate {predicate.__name__} is not returning "
                  "a frozen set, this will soon be required behaviour",
                  DeprecationWarning,
              )
              coverage = frozenset(
                  i
                  for i, (record_1, record_2) in enumerate(pairs)
                  if not frozenset(predicate(record_1)).isdisjoint(
                      predicate(record_2, target=True)
                  )
              )
          if coverage:
              predicate_cover[predicate] = coverage
  
      return predicate_cover
  
imports: from __future__ import annotations
  import collections
  import functools
  import itertools
  import logging
  import math
  import random
  from abc import ABC
  from typing import TYPE_CHECKING, overload
  from warnings import warn
  from .None import blocking, branch_and_bound
label_desc: Use image node_id 4 for calling the BlockLearner obj's underlying member method code with example usage: obj.cover(pairs, index_predicates) and returns: predicate_cover