Group by merge

merge.py

import itertools

def merge_components(cs):
    while True:
        for (i, a), (j, b) in itertools.combinations(enumerate(cs), 2):
            if a[0] == b[0]:
                a[1].extend(b[1])
                del cs[j]
                break
        else:
            break
    return cs

merge_components([
    ("foo", [1, 2, 3]),
    ("bar", [1, 2, 3]),
    ("foo", [1, 2, 3]),
    ("foo", [1, 2, 3]),
    ("bar", [1, 2, 3]),
])