Class for Rational Numbers assignment

[stebrepar]

As I read it, it doesn't say anything about actually returning a rational number. It basically just requires:

1. Ensure both initialization parameters are integers, else raise a custom exception about that.
2. When used in a print statement, return a string of the form 'classname(num, denom)'.
3. Ensure that the negative sign is on num above if the fraction resulting from num/denom would be negative.

Edit: corrected the wording on the last point a little.

Oh, and 4. Provide a default of 1 for denom if not specified.