How to debug "too many values to unpack (expected 1)" for the function call

Hello,
Looking for help to debug the following call to the function which has its return object assigned to one variable:

numba.core.errors.TypingError: Failed in nopython mode pipeline (step: nopython frontend)
Internal error at <numba.core.typeinfer.CallConstraint object at 0x16862ab90>.
Failed in object mode pipeline (step: object mode frontend)
not enough values to unpack (expected 1, got 0)
During: resolving callee type: type(CPUDispatcher(<function itslive_lsqfit_annual at 0x158a41c60>))
During: typing of call at /Users/.../itslive_composite.py (2091)

Enable logging at debug level for details.

File "itslive_composite.py", line 2091:
def cubelsqfit2_parallel_numba(
    <source elided>
            all_results = \
                itslive_lsqfit_annual(
                ^

I enabled debug logging with NUMBA_DEBUG_FRONTEND=1 and see that return object is being constructed as expected:

$1560build_list.12 = build_list(items=[Var(A, itslive_composite.py:812), Var(amp_error, itslive_composite.py:812), Var(ph, itslive_composite.py:812), Var(offset, itslive_composite.py:778), Var(slope, itslive_composite.py:778), Var(se, itslive_composite.py:778), Var(count_image_pairs, itslive_composite.py:811)]) ['$1560build_list.12', 'A', 'amp_error', 'count_image_pairs', 'offset', 'ph', 'se', 'slope']
    $1566build_list.15 = build_list(items=[Var(results_valid.1, itslive_composite.py:645), Var(init_runtime1, itslive_composite.py:650), Var(init_runtime2, itslive_composite.py:651), Var(init_runtime3, itslive_composite.py:652), Var(iter_runtime, itslive_composite.py:653), Var($1560build_list.12, itslive_composite.py:907), Var(global_i, itslive_composite.py:590), Var(global_j, itslive_composite.py:590)]) ['$1560build_list.12', '$1566build_list.15', 'global_i', 'global_j', 'init_runtime1', 'init_runtime2', 'init_runtime3', 'iter_runtime', 'results_valid.1']
    $1568return_value.16 = cast(value=$1566build_list.15) ['$1566build_list.15', '$1568return_value.16']
    return $1568return_value.16              ['$1568return_value.16']

I guess I am confused by the error message as I am assigning results of the itslive_lsqfit_annual() to “all_results” which is a list. The error message says “not enough values to unpack (expected 1, got 0)” - would it be related to any other function I am calling internally within the function or is it complaining about one of the input parameters types? Any help on how to debug it is greatly appreciated!

Using numba 0.58.0 on OS X M1

Can you provide minimal complete reproducible python code example of the problem?