Undefined method `confirmation' for #<Dry

1

I’m using confirmation as described in the docs but I get this error

(undefined methodconfirmation’ for #Dry::Validation::Schema::Rule:0x0000562370d6afd0)`

  class UserForm < Reform::Form
      property(:username)
      property(:password)
      property(:is_client_administrator)

      validation do 
        required(:username).filled(&:str?)
        required(:password).filled(&:str?)
        required(:password).confirmation
      end
    en