Pass kwargs to starmap while using Pool in Python

You can create a wrapper around pool.starmap that also accepts an iterator of over kwargs dictionaries.

from itertools import repeat

def starmap_with_kwargs(pool, fn, args_iter, kwargs_iter):
    args_for_starmap = zip(repeat(fn), args_iter, kwargs_iter)
    return pool.starmap(apply_args_and_kwargs, args_for_starmap)

def apply_args_and_kwargs(fn, args, kwargs):
    return fn(*args, **kwargs)

Then you can call it in your case as:

args_iter = zip(repeat(project_name), api_extensions)
kwargs_iter = repeat(dict(payload={'a': 1}, key=True))
branches = starmap_with_kwargs(pool, fetch_api, args_iter, kwargs_iter)