How to compute diff stats (insertions, deletions) in Python

import re
from collections import Counter


def parse_diff(diff_text):
    insertions = 0
    deletions = 0
    for line in diff_text.splitlines():
        if line.startswith("+") and not line.startswith("+++"):
            insertions += 1
        elif line.startswith("-") and not line.startswith("---"):
            deletions += 1
    return insertions, deletions


def diff_stats(diff_text):
    ins, dels = parse_diff(diff_text)
    return {
        "insertions": ins,
        "deletions": dels,
        "total_changes": ins + dels,
    }


if __name__ == "__main__":
    sample_diff = """diff --git a/example.txt b/example.txt
--- a/example.txt
+++ b/example.txt
@@ -1,4 +1,4 @@
 Hello world
-old line removed
+new line added
+another insertion
 unchanged line
"""
    stats = diff_stats(sample_diff)
    print(f"Insertions: {stats['insertions']}")
    print(f"Deletions: {stats['deletions']}")
    print(f"Total changes: {stats['total_changes']}")