Short JavaScript OR Python Script

Hi All,

Simply put, I need a short Python OR JavaScript (your preference) script to do the following;
- Fetch JSON Object via GET API Call to https://data.vatsim.net/v3/vatsim-data.json [No Authenticiation Required]
- I want to extract only the objects called "controllers" and "atis"
- Then return the parsed object to give just the "callsign" and matching "frequency" for each sub-object within "controllers" and "atis".
[example]
"callsign": "1859105_OBS",
"frequency": "199.998",
[/example]

You can view the data via web browser here: https://data.vatsim.net/v3/vatsim-data.json

Thanks in advance.