docstr: :return: list of OnnxInput
docstr_tok: [":","return",":","list","of","OnnxInput"]
code: def _extract_model_inputs(self):
      """
      :return: list of OnnxInput
      """
      input = self._input_list[0]
      if isinstance(input.zvalue, np.ndarray):
          self.is_batch = False
          return [self._to_zoo_input(input, is_constant=True)]
      else:
          self.is_batch = True
          return [self._to_zoo_input(input)]
  
file_path: analytics-zoo/pyzoo/zoo/pipeline/api/onnx/mapper/unsqueeze.py
imports: from zoo.pipeline.api.onnx.mapper.operator_mapper import OperatorMapper
  import zoo.pipeline.api.keras.layers
  import numpy
  from zoo.pipeline.api.autograd import Parameter
  import bigdl.nn.layer
  import zoo.pipeline.api.autograd
label_desc: Use image node_id 2 for calling the UnsqueezeMapper obj's underlying member method code with example usage: obj._extract_model_inputs() and returns: list, list