def parse_string_literal(string):
    """Evaluate a string with certain special values, or return the string. Any
    further parsing must be done outside this module, as this is as specialized
    as we're willing to be in assuming/interpreting what a string is supposed
    to mean.

    Parameters
    ----------
    string : string

    Returns
    -------
    val : bool, None, or str

    Examples
    --------
    >>> print(parse_string_literal('true'))
    True

    >>> print(parse_string_literal('False'))
    False

    >>> print(parse_string_literal('none'))
    None

    >>> print(parse_string_literal('something else'))
    'something else'

    """
    if string.strip().lower() == 'true':
        return True
    if string.strip().lower() == 'false':
        return False
    if string.strip().lower() == 'none':
        return None
    return string