code: def setUpClass(cls):
      super(VariantCallerCacheTests, cls).setUpClass()
      cls.raw_caller = PlaceholderVariantCaller(
          0.1, 50, use_cache_table=False
      )
      cls.cache_caller = PlaceholderVariantCaller(
          0.1,
          50,
          use_cache_table=True,
          max_cache_coverage=_CACHE_COVERAGE,
      )
  
imports: from unittest import mock
  from absl.testing import absltest
  from absl.testing import parameterized
  import numpy
  import numpy.testing
  from third_party.nucleus.util import variant_utils
  from third_party.nucleus.util import variantcall_utils
  from deepvariant import testdata
  from deepvariant import variant_caller
  from deepvariant.protos import deepvariant_pb2
label_desc: Use image node_id 1 for calling the VariantCallerCacheTests obj's underlying member method code with example usage: obj.setUpClass(cls) without return types