from typing import Mapping


def nop(string: str, _: Mapping[str, str]) -> str:
    """No operation parser, returns given string unchanged.

    This exists primarily as a default for when no parser is given as the use
    of `lift(str)` is recommended when the parsed value is supposed to be a
    string.

    :param string:
        String to return.
    :param _:
        Mapping of tag attributes.  Not used by this function.

    :return:
        The given `string`.
    """
    return string