I have a document such as:

```
{'my_key':  '2019-carbeureter'}

```

I want to search for '*2019*'

```
db.collection.find({'my_key': query_string } # isn't working with the following

query_string = "/2019/"   # doesn't work
query_string = r"/2019/"  # same thing
query_string = ".*2019.*" # doesn't work

```

This other SO question addresses it in native mongoDB, 
but how do I do this in Python using pymongo?
[How to query MongoDB with "like"?](https://stackoverflow.com/questions/3305561/how-to-query-mongodb-with-like)