New spec

[rollinger]

Our specification of the compression decompression has change to make grzip even more powerful. We now only compress characters that repeat 5 or more times. The other we leave as is. Also we remove the outer commas.

"aaaaaaaaaabbcccddddeeeeeXXXXXXfgh" -> "(10,a)bbcccdddd(5,e)(6,X)fgh"

• Please write a further compress function to reflect the new specification.
• Make the compression_threshold a parameter to the function. If the threshold changed to 3, then all 3-fold repetitions would be compressed.
• Also make the delimiter a parameter to the function.
• Make a good and clear docstring at the head of the function.
• at the start of the function, check that expanded_string is a string of len > 0, threshold is >= 2 and delimiter has two elements.

Function Signature:

def compress_new_spec(expanded_string, threshold=5, delimiter=["(",")"]):
    return compressed_string