import re


def num_project(s):
    """
    Cf. https://fatcat.wiki/release/6b5yupd7bfcw7gp73hjoavbgfq,
    https://fatcat.wiki/release/7hgzqz3hrngq7omtwdxz4qx34u

    Unify every occurence of a digit (or group of digits).
    """
    return re.sub(r'\d+', '<NUM>', s)