How to use the mutmut.cache.filename_and_mutation_id_from_pk function in mutmut

def get_mutations_by_file_from_cache(mutation_pk):
    from mutmut.cache import filename_and_mutation_id_from_pk
    filename, mutation_id = filename_and_mutation_id_from_pk(int(mutation_pk))
    return {filename: [mutation_id]}

def do_apply(mutation_pk, dict_synonyms, backup):
    """Apply a specified mutant to the source code

    :param mutation_pk: mutmut cache primary key of the mutant to apply
    :type mutation_pk: str

    :param dict_synonyms: list of synonym keywords for a python dictionary
    :type dict_synonyms: list[str]

    :param backup: if :obj:`True` create a backup of the source file
        before applying the mutation
    :type backup: bool
    """
    filename, mutation_id = filename_and_mutation_id_from_pk(int(mutation_pk))

    update_line_numbers(filename)

    context = Context(
        mutation_id=mutation_id,
        filename=filename,
        dict_synonyms=dict_synonyms,
    )
    mutate_file(
        backup=backup,
        context=context,
    )

if filename.startswith('test_') or filename.endswith('__tests.py'):
                    continue
                update_line_numbers(filename)
                add_mutations_by_file(mutations_by_file, filename, dict_synonyms, config)
    else:
        try:
            int(argument)
        except ValueError:
            filename = argument
            if not os.path.exists(filename):
                raise click.BadArgumentUsage('The run command takes either an integer that is the mutation id or a path to a file to mutate')
            update_line_numbers(filename)
            add_mutations_by_file(mutations_by_file, filename, dict_synonyms, config)
            return

        filename, mutation_id = filename_and_mutation_id_from_pk(int(argument))
        update_line_numbers(filename)
        mutations_by_file[filename] = [mutation_id]