code: def _create_placeholder(node):
      node.parse_from_attr()
      shape = []
      dtype = node.attr["dtype"]
      if types.is_tensor(node.datatype):
          shape = node.datatype.get_shape()
          shape = tuple(
              get_new_symbol() if s is None or s < 0 else s
              for s in shape
          )
      return mb.placeholder(shape, dtype=dtype)
  
imports: import six
  import logging
  from coremltools.converters.mil.input_types import InputType, TensorType, ImageType, RangeDim, _get_shaping_class
  from coremltools.converters.mil.input_types import Shape
  from coremltools.converters.mil.mil.var import Var
  from coremltools.converters.mil.mil import get_new_symbol
  from coremltools.converters.mil.mil.types.symbolic import is_symbolic
  from coremltools.converters.mil.mil import types
  from .basic_graph_ops import topsort, simple_topsort
  from .convert_utils import convert_graph
  from coremltools.converters.mil.mil import Builder
  from coremltools.converters.mil.mil import Program
  from coremltools.converters.mil.mil import Function
  from .ssa_passes.tf_passes import tensorflow_passes
  from coremltools.converters._profile_utils import _profile
label_desc: Use image node_id 4 for calling the TFConverter obj's underlying member method code with example usage: obj._create_placeholder(node) and returns: mb