Implemented sum() builtin functionality for other types.

[nicklambourne]

Changes

Implemented python sum() builtin functionality for other datatypes including Strings, Sets, FrozenSets, Dict, Range, Bytes and Bytearrays. Calling sum on these datatypes generally returns something type-specific (e.g. bytes returns the sum of each byte's ASCII value) .

N.B. The tests for Set and FrozenSet occasionally fail nondeterministically (though only when provided invalid input - specifically a mix of ints, floats and strings) due to fact that their values are are stored in Python dicts and dicts don't (yet) maintain order. If anyone can see a way around this, I'd love to know. In the interim I've disabled the tests for Set and FrozenSet, but kept the functionality (which works, it may just return a different TypeError message).

Problem

The unique sum() functionality across the less commonly used data types had not been implemented.

Fixes

Contributes to fixing #47

PR Checklist:

• All new features have been tested
• All new features have been documented
• I have read the CONTRIBUTING.md file
• I will abide by the code of conduct

[freakboy3742]

👍

We have a couple of mechanisms for dealing with non-deterministic key-ordering, based on output substitution; if you search for substitutions in the test directory, you should be able to find some examples for working around the problem.