Adapted to Python from this kata.

• Create a simple string calculator with a method signature:

  add(str numbers) -> int

• The method can take up to two numbers, separated by commas, and will return their sum.

  • for example '' or '1' or '1,2' as inputs.
  • for an empty string it will return 0

• Allow the add method to handle an unknown amount of numbers

• Allow the add method to handle new lines between numbers (instead of commas).

  • The following input is ok: '1\n2,3' (will equal 6)
  • The following input is NOT ok: '1,\n' (not need to prove it - just clarifying)

• Support different delimiters

  • To change a delimiter, the beginning of the string will contain a separate line that looks like this:

      '//[delimiter]\n[numbers…]'

  for example '//;\n1;2' should return 3 where the default delimiter is ';'.

  • The first line is optional. All existing scenarios should still be supported

• 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.

STOP HERE if you are a beginner. Continue if you can finish the steps so far in less than 30 minutes.

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

• Delimiters can be of any length with the following format:

  '//[delimiter]\n'

  for example: '//[***]\n1***2***3' should return 6

  Allow multiple delimiters like this:

  '//[delim1][delim2]\n'

  for example '//[*][%]\n1*2%3' should return 6.

• Make sure you can also handle multiple delimiters with length longer than one character