def METHOD_NAME():
    """Find the modules in sys.modules which cause "mod" to be imported."""
    # If we've run this function before, return the same result.
    global KNOWN_FTZ
    if KNOWN_FTZ:
        return KNOWN_FTZ
    # Start by determining our baseline: the FTZ and sys.modules state in a fresh
    # process which has only imported this module and nothing else.
    always_enables_ftz, always_imports = run_in_process(always_imported_modules)
    if always_enables_ftz:
        raise RuntimeError("Python is always in FTZ mode, even without imports!")
    CHECKED_CACHE.update(always_imports)
    # Next, we'll search through sys.modules looking for a package (or packages) such
    # that importing them in a new process sets the FTZ state.  As a heuristic, we'll
    # start with packages known to have ever enabled FTZ, then top-level packages as
    # a way to eliminate large fractions of the search space relatively quickly.
    def key(name):
        """Prefer known-FTZ modules, then top-level packages, then alphabetical."""
        return (name not in KNOWN_EVER_CULPRITS, name.count("."), name)
    # We'll track the set of modules to be checked, and those which do trigger FTZ.
    candidates = set(sys.modules) - CHECKED_CACHE
    triggering_modules = {}
    while candidates:
        mod = min(candidates, key=key)
        candidates.discard(mod)
        enables_ftz, imports = run_in_process(modules_imported_by, mod)
        imports -= CHECKED_CACHE
        if enables_ftz:
            triggering_modules[mod] = imports
            candidates &= imports
        else:
            candidates -= imports
            CHECKED_CACHE.update(imports)
    # We only want to report the 'top level' packages which enable FTZ - for example,
    # if the enabling code is in `a.b`, and `a` in turn imports `a.b`, we prefer to
    # report `a`.  On the other hand, if `a` does _not_ import `a.b`, as is the case
    # for `hypothesis.extra.*` modules, then `a` will not be in `triggering_modules`
    # and we'll report `a.b` here instead.
    prefixes = tuple(n + "." for n in triggering_modules)
    result = {k for k in triggering_modules if not k.startswith(prefixes)}
    # Suppose that `bar` enables FTZ, and `foo` imports `bar`.  At this point we're
    # tracking both, but only want to report the latter.
    for a in sorted(result):
        for b in sorted(result):
            if a in triggering_modules[b] and b not in triggering_modules[a]:
                result.discard(b)
    # There may be a cyclic dependency which that didn't handle, or simply two
    # separate modules which both enable FTZ.  We already gave up comprehensive
    # reporting for speed above (`candidates &= imports`), so we'll also buy
    # simpler reporting by arbitrarily selecting the alphabetically first package.
    KNOWN_FTZ = min(result)  # Cache the result - it's likely this will trigger again!
    return KNOWN_FTZ