In Python 3

String Calculator

Create a simple StringCalculator class with a method that returns an integer called Add(string numbers)

The method can take 0, 1 or 2 numbers, and will return their sum (for an empty string it will return 0) for example or 1 or 1,2.

Start with the simplest test case of an empty string and move to 1 and two numbers

Remember to solve things as simply as possible so that you force yourself to write tests you did not think about

Remember to refactor after each passing test

Allow the Add method to handle an unknown amount of numbers

Calling Add with a negative number will throw an exception negatives not allowed - and the negative that was passed.if there are multiple negatives, show all of them in the exception message. There should be a test case that tests for the exception.

Numbers bigger than 1000 should be ignored, so adding 2 + 1001 = 2

Remember that your input is one string containing 1 or more numbers separated by commas.

You will need a minimum of 4 test cases.