code: def test_corpus_metadata(corpus):
      result = corpus.agg_metadata("congress", min)
      assert result and isinstance(result, int)
      min_dt = corpus.agg_metadata("date", min)
      max_dt = corpus.agg_metadata("date", max)
      assert min_dt < max_dt
      result = corpus.agg_metadata("speaker_name", collections.Counter)
      assert result and isinstance(result, collections.Counter)
  
imports: import collections
  import itertools
  import re
  import pytest
  from spacy.tokens import Span
  import textacy
  import textacy.datasets
  import textacy.extract
  import textacy.preprocessing
label_desc: Use image node_id 12 for calling a global function with example usage: test_corpus_metadata(corpus) without return types