How to post-train BERT model on custom dataset

Question

I want to get the BERT word embeddings which will be used in another down-stream task later. I have a corpus for my custom dataset and want to further pre-train the pre-trained Huggingface BERT base model. I think this is called post-training. How can I do this using Huggingface transformers? Can I use transformers.BertForMaskedLM?