def initialize(amount:, currency:, user:, page_id:, redirect_flow_id:, session_token:, extra_params: {})
        @page_id = page_id
        @original_amount_in_cents = (amount.to_f * 100).to_i # Price in pence/cents
        @original_currency = currency.try(:upcase)
        @redirect_flow_id = redirect_flow_id