Meltano

Hello, I'm trying to use the mapper <https://hub.meltano.com/mappers/meltano-map-transformer/|meltano-map-transformer> to map a column that is a dictionary. Is it possible to map a the `value` of a specific `key` to `null`? I've tried a few thing but none works:
```# First try
params.field1: null

# Second try
params.['field1']: null

# Third try
params: |
  params['field1'] = None
  params```
Any idea on how to achieve this?

Maybe

```          params: "{**params, 'field1': None}"```
or if you're using Python 3.9 or newer

```          params: "params | {'field1': None}"```

This might also be of interest: <https://sdk.meltano.com/en/latest/stream_maps.html#compound-expressions>

i.e.

```          params: "{k: None if k == 'field1' else v for k, v in params.items()}"```

Just tried it and it worked very well for dictionaries! Thanks

Awesome, no problem! :slightly_smiling_face: