import re


def __highlight_fuzzy_string(target: str, search_value: str) -> str:
    """
    Highlight every existence of target in the search_value with the <em> tag.
    This <em> tag can be replaces with any other tag.

    :param target: the haystack to search in
    :param search_value: the needle to search for target
    :return: a highlighted html string
    """
    res = re.compile(re.escape(search_value), re.IGNORECASE)
    return res.sub('<em>{}</em>'.format(search_value), target)