dry-validation conditional validation

form.rb

class Fund::CreateCallForm < BaseForm  
  property :type
  property :fund
  
  validation do
    required(:type) { filled? & included_in?(TRANSACTION_TYPES['Fund::Call']) }
  end
  
  validation if: -> (results) { rebalance? } do
    required(:fund).filled
  end

  def rebalance?
    self.type == 'rebalance'
  end
end