def METHOD_NAME(cls, fieldname, value):
    """
    A :class:`~urllib3.fields.RequestField` factory from old-style tuple parameters.
    Supports constructing :class:`~urllib3.fields.RequestField` from
    parameter of key/value strings AND key/filetuple. A filetuple is a
    (filename, data, MIME type) tuple where the MIME type is optional.
    For example::
        'foo': 'bar',
        'fakefile': ('foofile.txt', 'contents of foofile'),
        'realfile': ('barfile.txt', open('realfile').read()),
        'typedfile': ('bazfile.bin', open('bazfile').read(), 'image/jpeg'),
        'nonamefile': 'contents of nonamefile field',
    Field names and filenames must be unicode.
    """
    if isinstance(value, tuple):
        if len(value) == 3:
            filename, data, content_type = value
        else:
            filename, data = value
            content_type = guess_content_type(filename)
    else:
        filename = None
        content_type = None
        data = value
    request_param = cls(fieldname, data, filename=filename)
    request_param.make_multipart(content_type=content_type)
    return request_param