Split problem statement

split.py

cases = [
    ('  mte  st m', ' ', ['', '', 'mte', '', 'st', 'm']),
    ('mtestm', ' ', ['mtestm']),
    ('mtestm', 'm', ['', 'test', '']),
    ('mmadfmm', 'm', ['', '', 'adf', '', '']),
    ('sfd   423', ' ', ['sfd', '', '', '423']),
    ('hello', ' ', ['hello']),
]
for i, (S, sep, expected_op) in enumerate(cases):
    op = split(S, sep)
    if op != expected_op:
        print(i, S, sep, op, expected_op)