Missing backend on an operator causes error when inserting PTQScalingNode

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What commit version of aidge do you use

• aidge_backend_cpu : 0.5.0
• aidge_backend_cuda : 0.5.1
• aidge_core : 0.5.1
• aidge_export_jacinto: 0.0.2
• aidge_onnx : 0.4.1
• aidge_quantization : 0.3.1

Problem description

In a YoloV3, I have a concat operator that does not have an associated backend because it is just a data manipulation operator. during the insertion step of scalaing node in the PTQ, the backend of the parent node is retrieved... except that the concat node does not have one! The registrar function therefore gives an error!

[ERROR] - Assertion failed: exists(key) in /projecc_path/aidge/aidge/aidge_core/include/aidge/utils/Registrar.hpp:88
[FATAL] - missing or invalid registrar key: for
[FATAL]   registrable object N5Aidge6Mul_OpE
[FATAL]   Did you include/import the corresponding module?
[FATAL]   If so, it is possible that the object is not yet supported.
[FATAL]   
[FATAL]   Available registrar keys are:
[FATAL]       cpu
Traceback (most recent call last):
  File "~project_path/examples/yolov3/yolov3.py", line 222, in <module>
    aidge_quantization.quantize_network(
RuntimeError: missing or invalid registrar key: NSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE for registrable object N5Aidge6Mul_OpE
Did you include/import the corresponding module?
If so, it is possible that the object is not yet supported.

added Bug 🐛 StatusTODO labels

set weight to 0

assigned to @mick94 and @bhalimi

changed the description

changed weight to 1 from 0

Should be fixed with !48 (merged).

closed