Update:
According to: PyTorch convert function for op ‘dictconstruct’ not implemented · Issue #1157 · apple/coremltools (github.com)
After changing my code from
model = transformers.SqueezeBertForSequenceClassification(config)
into
model=transformers.SqueezeBertForSequenceClassification.from_pretrained(‘squeezebert/squeezebert-uncased’, return_dict=False)
I was able to convert it successfully!