def bank_account_number=(number)
      raise ArgumentError.new('Bank account number cannot be nil') if number.nil?
      nr_str = "#{number}".gsub(/\s/,'')
      raise ArgumentError.new('Bank account number too long, max 10 allowed') if nr_str.length > 10
      raise ArgumentError.new('Bank account number cannot be 0') if nr_str == '0'

      @bank_account_number = nr_str.to_i
    end
def bank_account_number=(number)
      raise ArgumentError.new('Bank account number cannot be nil') if number.nil?
      nr_str = "#{number}".gsub(/\s/,'')
      raise ArgumentError.new('Bank account number too long, max 10 allowed') if nr_str.length > 10
      raise ArgumentError.new('Bank account number cannot be 0') if nr_str == '0'

      @bank_account_number = nr_str.to_i
    end
Cast given account number to integer. Strips spaces and leading zeros
 from the bank account number.
 DTA relies on integers for checksums and field values.
 @param [String|Integer] number