def parse_dict_header(value, cls=dict):
    """Parse lists of key, value pairs as described by RFC 2068 Section 2 and
    convert them into a python dict (or any other mapping object created from
    the type with a dict like interface provided by the `cls` argument):

    >>> d = parse_dict_header('foo="is a fish", bar="as well"')
    >>> type(d) is dict
    True
    >>> sorted(d.items())
    [('bar', 'as well'), ('foo', 'is a fish')]

    If there is no value for a key it will be `None`:

    >>> parse_dict_header('key_without_value')
    {'key_without_value': None}

    To create a header from the :class:`dict` again, use the
    :func:`dump_header` function.

    .. versionchanged:: 0.9
       Added support for `cls` argument.

    :param value: a string with a dict header.
    :param cls: callable to use for storage of parsed results.
    :return: an instance of `cls`
    """
    result = cls()
    if not isinstance(value, text_type):
        # XXX: validate
        value = bytes_to_wsgi(value)
    for item in _parse_list_header(value):
        if "=" not in item:
            result[item] = None
            continue
        name, value = item.split("=", 1)
        if value[:1] == value[-1:] == '"':
            value = unquote_header_value(value[1:-1])
        result[name] = value
    return result