def create_signature(payment_transaction)
      control_code = ''

      signature_definition.each do |property_path|
        control_code << PropertyAccessor.get_value(payment_transaction, property_path).to_s
      end

      Digest::SHA1.hexdigest control_code
    end
def create_signature(payment_transaction)
      control_code = ''

      signature_definition.each do |property_path|
        control_code << PropertyAccessor.get_value(payment_transaction, property_path).to_s
      end

      Digest::SHA1.hexdigest control_code
    end
Generates the control code is used to ensure that it is a particular
 Merchant (and not a fraudster) that initiates the transaction.

 @param    payment_transaction   [PaymentTransaction]    Payment transaction to generate control code

 @return                         [String]                Generated control code