def exchange(from, to, fixnum)
      @from_currency = from.upcase.to_sym
      @to_currency = to.upcase.to_sym

      validate_currency

      ex_rate = exchange_rate

      validate_rate(ex_rate)

      ex_rate.to_f * fixnum
    end
def exchange(from, to, fixnum)
      @from_currency = from.upcase.to_sym
      @to_currency = to.upcase.to_sym

      validate_currency

      ex_rate = exchange_rate

      validate_rate(ex_rate)

      ex_rate.to_f * fixnum
    end
Receive the amount of you desire currency.

 @param [String, String, Numeric] other currency to exchange to.

 @return [amount]

 @example
 currency_converter = CurrencyConverter::XE.new
 currency_converter.exchange('USD', 'EUR', 100)
 currency_converter.exchange('USD', 'INR', 100)