code: def _get_input_names(spec):
      """
      Returns a list of the names of the inputs to this model.
      :param spec: The model protobuf specification
      :return: list of str A list of input feature names
      """
      retval = [feature.name for feature in spec.description.input]
      return retval
  
imports: import math
  import numpy
  import os
  import six
  import warnings
  import sys
  from coremltools.proto import Model_pb2
  from coremltools.models._deprecation import deprecated
  from .._deps import _HAS_SKLEARN
label_desc: Use image node_id 28 for calling a global function with example usage: _get_input_names(spec) and returns: retval