code: def _default_op_selector(const_op):
      if (
          not isinstance(const_op, _Operation)
          or const_op.op_type != "const"
      ):
          raise ValueError(
              "Input of the op_selector must be type of const Operation, got {}.".format(
                  type(const_op)
              )
          )
      return (
          const_op.val.val.size > _DEFAULT_MIN_WEIGHT_SIZE_TO_COMPRESS
      )
  
file_path: coremltools/coremltools/models/ml_program/compression_utils.py
imports: import numpy
  from coremltools.converters.mil import Operation
  from coremltools.models._deprecation import deprecated
  from coremltools.optimize.coreml import OpLinearQuantizerConfig, OpMagnitudePrunerConfig, OpPalettizerConfig, OpThresholdPrunerConfig, OptimizationConfig
  from coremltools.optimize.coreml import linear_quantize_weights, decompress_weights, palettize_weights, prune_weights
label_desc: Use image node_id 1 for calling a global function with example usage: _default_op_selector(const_op) and returns: unknown