Meltano

trying to follow this <https://sdk.meltano.com/en/latest/stream_maps.html#add-a-property-with-a-string-literal-value|doc>

this seemed straight forward - so hopefully I'm just missing something small

I tried with just "" not using the \ to escape and that didn't work

also map works fine without the a_new_field part in it

```  mappers:
  - name: meltano-map-transformer
    variant: meltano
    pip_url: git+<https://github.com/MeltanoLabs/meltano-map-transform.git>
    mappings:
    - name: alias_and_source_system
      config:
        stream_maps:
          dbo-ord:
            source_system: str('location#1')
            __alias__: dbo-ordv2```

ok - that works if you wrap it in a str()