def parse_mix(raw: str) -> list:
    """Parse a raw string that indicates a mix into a list. For example, 
    "3/2/1" will be converted to [0.5, 0.333, 0.166]

    """
    if type(raw) is not str:
        raise TypeError("parse_mix: argument is of invalid type, must be string")

    raw_splits = raw.split("/")

    #Get rid of non-numeric gibberish
    splits = [int(split) for split in raw_splits if split.isnumeric()]

    total = sum(splits)

    #Convert to fraction
    return [(split / total) for split in splits]