class_docstr: A placeholder VariantCaller.
  
  This class provides a get_candidates implementation and so allows
  the base class to be instantiated and its methods tested.
class_docstr_tok: ["A","placeholder","VariantCaller",".","This","class","provides","a","get_candidates","implementation","and","so","allows","the","base","class","to","be","instantiated","and","its","methods","tested","."]
code: def __init__(
      self,
      p_error,
      max_gq,
      gq_resolution=1,
      use_cache_table=False,
      max_cache_coverage=100,
  ):
      super(PlaceholderVariantCaller, self).__init__(
          options=_reference_model_options(
              p_error, max_gq, gq_resolution
          ),
          use_cache_table=use_cache_table,
          max_cache_coverage=max_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 to create a new PlaceholderVariantCaller object from inherited base classes: variant_caller with example: obj = PlaceholderVariantCaller(p_error, max_gq, gq_resolution, use_cache_table, max_cache_coverage)