How to use the mutmut.cache.SourceFile.get function in mutmut

def get_cached_mutation_statuses(filename, mutations, hash_of_tests):
    sourcefile = SourceFile.get(filename=filename)
    assert sourcefile

    line_obj_by_line = {}

    result = {}

    for mutation_id in mutations:
        if mutation_id.line not in line_obj_by_line:
            line_obj_by_line[mutation_id.line] = Line.get(sourcefile=sourcefile, line=mutation_id.line, line_number=mutation_id.line_number)
        line = line_obj_by_line[mutation_id.line]
        assert line
        mutant = Mutant.get(line=line, index=mutation_id.index)
        if mutant is None:
            mutant = get_or_create(Mutant, line=line, index=mutation_id.index, defaults=dict(status=UNTESTED))

        result[mutation_id] = mutant.status

def update_mutant_status(file_to_mutate, mutation_id, status, tests_hash):
    sourcefile = SourceFile.get(filename=file_to_mutate)
    line = Line.get(sourcefile=sourcefile, line=mutation_id.line, line_number=mutation_id.line_number)
    mutant = Mutant.get(line=line, index=mutation_id.index)
    mutant.status = status
    mutant.tested_against_hash = tests_hash

def cached_mutation_status(filename, mutation_id, hash_of_tests):
    sourcefile = SourceFile.get(filename=filename)
    assert sourcefile
    line = Line.get(sourcefile=sourcefile, line=mutation_id.line, line_number=mutation_id.line_number)
    assert line
    mutant = Mutant.get(line=line, index=mutation_id.index)
    if mutant is None:
        mutant = get_or_create(Mutant, line=line, index=mutation_id.index, defaults=dict(status=UNTESTED))

    if mutant.status == OK_KILLED:
        # We assume that if a mutant was killed, a change to the test
        # suite will mean it's still killed
        return OK_KILLED

    if mutant.tested_against_hash != hash_of_tests or \
            mutant.tested_against_hash == NO_TESTS_FOUND or \
            hash_of_tests == NO_TESTS_FOUND:
        return UNTESTED