LAMBDA WORKS IN EXCEL, NOT IN EXCEL LABS EDITOR

HI ALL:

I have a Lambda that works in Excel -- but if I try to edit it in Excel Labs Lambda Editor it generates an Error.

The result is that I cannot name the LAMBDA for general use ( 

The Editor gives the following error : "Save failed: The argument is invalid or missing or has an incorrect format."

Thanks in advance

Below is the code
BTW -- it works, but its not 100% tested .

=LAMBDA(ARRAY, target_buckets, match_mode,
    LET(
        XMATCH3, LAMBDA(vector, target, match_mode,
            LET(
                _PURPOSE, "  XMATCH with different match_mode
                         match_mode, 
                         =-1 =>index of  # lesthan target, 
                         = 0  =>closest to target,
                         = > 1 # greater than target  ",
                index_LT, XMATCH(target, vector, 1),
                index_closest, XMATCH(MIN(vector - target), vector - target, 0),
                index_GT, XMATCH(target, vector, -1),
                INDEX(HSTACK(index_LT, index_closest, index_GT), match_mode + 2)
            )
        ),
        _c1, "   ",
        _PURPOSE, "
                Given a random array of numbers,
                returns 4 valued vector
                with HUMAN READABLE  AXES
                MIN_VALUE, MAX_VALUE, DELTA, #_BUCKETS
                -- great for HISTOGRAMS & GRAPHS                
                ",
        _INPUTS, "ARRAY          : an array of values
                    target_buckts  : minimum # of buckets",
        _OUTPUTS, "HUMAN READABLE
                    MIN_VALUE, MAX_VALUE, DELTA",
        _COMPATABILITY, "WORKS IN EXCEL AND GOOGLE SHEETS",
        _c2, "   ",
        imin, MIN(ARRAY),
        imax, MAX(ARRAY),
        idiff, imax - imin,
        idelta, idiff / target_buckets,
        scale, 10 ^ (FLOOR(LOG10(idelta), 1)),
        scaled_delta, idelta / scale,
        standard_deltas, {1, 2, 2.5, 5, 10},
        scaled_delta_index, XMATCH3(standard_deltas, scaled_delta, match_mode),
        optimal_delta, INDEX(standard_deltas, scaled_delta_index) * scale,
        optimal_diff, CEILING(idiff / optimal_delta, 1) * optimal_delta,
        optimal_start, IF(
            imin > 0,
            CEILING(imin / optimal_delta, 1) * optimal_delta,
            FLOOR(imin / optimal_delta, 1) * optimal_delta
        ),
        temp_end, optimal_start + optimal_diff,
        optimal_end, IF(temp_end <= imax, temp_end, temp_end + optimal_delta),
        optimal_buckets, (optimal_end - optimal_start) / optimal_delta,
        result, HSTACK(optimal_start, optimal_end, optimal_delta, optimal_buckets),
        result
    )
)({1,2,3}, 10, 1)