def impl_ret_borrowed(ctx, builder, retty, ret):
    """
    The implementation returns a borrowed reference.
    This function automatically incref so that the implementation is
    returning a new reference.
    """
    if ctx.enable_nrt:
        ctx.nrt.incref(builder, retty, ret)
    return ret

    The implementation returns a borrowed reference.
    This function automatically incref so that the implementation is
    returning a new reference.
    
numba/core/imputils.py