python35Packages.vega: disable python{2,35}, abandonded
python35Packages.vega: disable python{2,35}, abandonded

```
  Processing ./vega-3.4.0-py2-none-any.whl
  ERROR: Package 'vega' requires a different Python: 2.7.18 not in '>=3.6.1'
  builder for '/nix/store/l6f04q9sk1a3n8rl4rscaz2w8xinygfr-python2.7-vega-3.4.0.drv' failed with exit code 1
```

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