code: def test_string_to_float(self):
      self.assertEqual(postprocessors.string_to_float("10"), 10.0)
      self.assertEqual(postprocessors.string_to_float("10."), 10.0)
      self.assertEqual(postprocessors.string_to_float("asdf"), -1.0)
      self.assertEqual(
          postprocessors.string_to_float("asdf", -2.0), -2.0
      )
  
file_path: text-to-text-transfer-transformer/t5/data/postprocessors_test.py
imports: from absl.testing import absltest
  import numpy
  from t5.data import postprocessors
label_desc: Use image node_id 1 for calling the PostprocessorsTest obj's underlying member method code with example usage: obj.test_string_to_float() without return types