def extract_subsection(conf: dict, section: str) -> dict:
    """Takes a nested dictionary and returns the dictionary corresponding to a dot-delimited sub-dict.

    >>> test_dict = {'foo': {'bar': {1: 42, 2: 55}}, 'baz': "Hello"}
    >>> extract_subsection(test_dict, "foo.bar")
    {1: 42, 2: 55}
    """

    for subsection in section.split("."):
        conf = conf[subsection]
    return conf