from typing import Tuple


def calculate_line_changes(diff: str) -> Tuple[int, int]:
    """Return a two-tuple (additions, deletions) of a diff."""
    additions = 0
    deletions = 0
    for line in diff.splitlines():
        if line[0] == "+" and not line.startswith("+++"):
            additions += 1
        elif line[0] == "-" and not line.startswith("---"):
            deletions += 1

    return additions, deletions