```ruby
BanList.for_format("pioneer") do
  format_start(
    "https://magic.wizards.com/en/articles/archive/news/announcing-pioneer-format-2019-10-21",
    "Bloodstained Mire" => "banned",
    "Flooded Strand" => "banned",
    "Polluted Delta" => "banned",
    "Windswept Heath" => "banned",
    "Wooded Foothills" => "banned",
  )
end
```

Add yesterday's Pioneer B&R changes
user
```ruby
BanList.for_format("pioneer") do
  format_start(
    "https://magic.wizards.com/en/articles/archive/news/announcing-pioneer-format-2019-10-21",
    "Bloodstained Mire" => "banned",
    "Flooded Strand" => "banned",
    "Polluted Delta" => "banned",
    "Windswept Heath" => "banned",
    "Wooded Foothills" => "banned",
  )

  change(
    "2019-11-04",
    "https://magic.wizards.com/en/articles/archive/news/november-4-2019-pioneer-banned-announcement",
    "Felidar Guardian" => "banned",
    "Leyline of Abundance" => "banned",
    "Oath of Nissa" => "banned",
  )
end
```
assistant