How to use the auditwheel.policy.lddtree_external_references function in auditwheel

# Get a list of all external libraries needed by ELFs in the wheel.
        needed_libs = {
            lib
            for elf in itertools.chain(full_elftree.values(),
                                       nonpy_elftree.values())
            for lib in elf['needed']
        }

        for fn in nonpy_elftree.keys():
            # If a non-pyextension ELF file is not needed by something else
            # inside the wheel, then it was not checked by the logic above and
            # we should walk its elftree.
            if basename(fn) not in needed_libs:
                full_elftree[fn] = nonpy_elftree[fn]
                full_external_refs[fn] = lddtree_external_references(
                    nonpy_elftree[fn], ctx.path)

    log.debug(json.dumps(full_elftree, indent=4))

    return (full_elftree, full_external_refs, versioned_symbols,
            uses_ucs2_symbols, uses_PyFPE_jbuf)

for key, value in elf_find_versioned_symbols(elf):
                    log.debug('key %s, value %s', key, value)
                    versioned_symbols[key].add(value)

                is_py_ext, py_ver = elf_is_python_extension(fn, elf)

                # If the ELF is a Python extention, we definitely need to
                # include its external dependencies.
                if is_py_ext:
                    full_elftree[fn] = elftree
                    uses_PyFPE_jbuf |= elf_references_PyFPE_jbuf(elf)
                    if py_ver == 2:
                        uses_ucs2_symbols |= any(
                            True for _ in elf_find_ucs2_symbols(elf))
                    full_external_refs[fn] = lddtree_external_references(
                        elftree,
                        ctx.path)
                else:
                    # If the ELF is not a Python extension, it might be
                    # included in the wheel already because auditwheel repair
                    # vendored it, so we will check whether we should include
                    # its internal references later.
                    nonpy_elftree[fn] = elftree

        if not platform_wheel:
            raise NonPlatformWheel

        # If at least one shared library exists in purelib, raise an error
        if shared_libraries_in_purelib:
            raise RuntimeError(
                (