Backoff by blocks when batch inserting data somewhere, and a few records tend to fail

unmerge_backoff.py

from collections import Iterable

def flatten(l):
  if not isinstance(l, Iterable):
    yield l
  else:
    for el in l:
      if isinstance(el, Iterable) and not isinstance(el, (str, bytes)):
        yield from flatten(el)
      else:
        yield el

def recursive_backoff(fn, data, **args):
  res = []

  try:
    res = fn(data, **args)
  except Exception as e:
    if len(data) == 1: return [None]
    l = len(data)
    res.append(recursive_backoff(fn, data[ :l//2], **args))
    res.append(recursive_backoff(fn, data[l//2: ], **args))
  return list(flatten(res))

def f(d, args=None):
  return (len(d) if (len(d) % 2 == 0) else 1/0)

recursive_backoff(f, [1,2,3,4,5,6,7,8,9,10,11], )