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.

def from_tuples(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