code: def test_c_reader(self):
      self.assertIsInstance(
          self.in_mem.c_reader, reference.InMemoryFastaReader
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing import absltest
  from absl.testing import parameterized
  import six
  from third_party.nucleus.io import fasta
  from third_party.nucleus.io.python import reference
  from third_party.nucleus.testing import test_utils
  from third_party.nucleus.util import ranges
label_desc: Use image node_id 15 for calling the InMemoryFastaReaderTests obj's underlying member method code with example usage: obj.test_c_reader() without return types