```ruby
class ConditionIsCustom < ConditionSimple
  def match?(card)
    return true if card.custom?
    false
  end

  def to_s
    "is:custom"
  end
end
```

Fix is:custom checking printing, not card
user
```ruby
class ConditionIsCustom < ConditionSimple
  def match?(printing)
    printing.card.custom?
  end

  def to_s
    "is:custom"
  end
end
```
assistant