Combine the overlap of one-dimensional intervals

Hello I gave a set of one-dimensional intervals and tried to combine their overlaps. Refer to "merging overlapping intervals" (Stack Overflow) and it's almost the same.

$ ./merger.py 
input: [[-25, -14], [-21, -16], [-20, -15], [-10, -7], [-8, -5], [-6, -3], [2, 4], [2, 3], [3, 6], [12, 15], [13, 18], [14, 17], [22, 27], [25, 30], [26, 29]]
output: [[-25, -14], [-10, -3], [2, 6], [12, 18], [22, 30]]

`merger.py`


#!/usr/bin/env python3
# -*- coding: utf-8 -*-

def merger(intervals):
    intervals.sort(key=lambda interval: interval[0])
    merged = [intervals[0]]
    for w in intervals:
        if w[0] > merged[-1][1]:
            merged.append(w)
        elif w[1] > merged[-1][1]:
            merged[-1][1] = w[1]
    return merged

intervals = [[-25, -14], [-21, -16], [-20, -15], [-10, -7], [-8, -5], [-6, -3], [2, 4], [2, 3], [3, 6], [12, 15], [13, 18], [14, 17], [22, 27], [25, 30], [26, 29]]
print(f"input: {intervals}")
print(f"output: {merger(intervals)}")