code: def test_span_squad_one_word(self):
      ref = "answer"
      ans_span = "start:1 end:1"
      context = "the answer"
  
      self.assertDictClose(
          metrics.span_squad(
              [{"answers": [ref], "context": context}], [ans_span]
          ),
          {"em": 100, "f1": 100},
      )
  
imports: from unittest import mock
  from absl.testing import absltest
  import numpy
  import seqio
  import sklearn.metrics
  from t5.evaluation import metrics
  from t5.evaluation import test_utils
label_desc: Use image node_id 12 for calling the MetricsTest obj's underlying member method code with example usage: obj.test_span_squad_one_word() without return types