message: change asserts for Sum
diff: @@ -903,7 +903,19 @@ void ONNXImporter::parseBias(LayerParams& layerParams, const opencv_onnx::NodePr
  opencv_onnx::NodeProto node_proto = node_proto_;
  const std::string& layer_type = node_proto.op_type();
  bool isSub = layer_type == "Sub";
  - CV_CheckEQ(node_proto.input_size(), 2, "");
  + CV_Assert((node_proto.input_size() == 2) || (layer_type == "Sum" && node_proto.input_size() > 2));
  +
  + if (layer_type == "Sum" && node_proto.input_size() > 2)
  + {
  + for (int i = 0; i < node_proto.input_size(); ++i)
  + {
  + if (layer_id.find(node_proto.input(i)) == layer_id.end())
  + {
  + CV_Error(Error::StsNotImplemented, "Sum of constants is not implemented for inputs > 2");
  + }
  + }
  + }
  +
  bool is_const_0 = layer_id.find(node_proto.input(0)) == layer_id.end();
  bool is_const_1 = layer_id.find(node_proto.input(1)) == layer_id.end();
  if (is_const_0 && is_const_1)
  