code: def _to_tensor(self):
      x = self.model_inputs[0]
      z = self.model_trainable_values[1]
      assert len(x.zvalue.shape) == 2, "we only accept 2D input"
  
      if "transA" in self.onnx_attr and self.onnx_attr["transA"]:
          # TODO: add transpose operator for this x = x.transpose()
          raise Exception("we don't support this for now")
      layer = zlayers.Dense(len(z))
      return layer(x.zvalue)
  
file_path: analytics-zoo/pyzoo/zoo/pipeline/api/onnx/mapper/gemm.py
imports: import numpy
  import zoo.pipeline.api.keras.layers
  from zoo.pipeline.api.onnx.mapper.operator_mapper import OperatorMapper
label_desc: Use image node_id 5 for calling the GemmMapper obj's underlying member method code with example usage: obj._to_tensor() and returns: layer