UpdateExtension.
        [Preview API] REST endpoint to update an extension.
        :param object upload_stream: Stream to upload
        :param str publisher_name: Name of the publisher
        :param str extension_name: Name of the extension
        :param bool bypass_scope_check: This parameter decides if the scope change check needs to be invoked or not
        :rtype: :class:`<PublishedExtension> <azure.devops.v5_1.gallery.models.PublishedExtension>`

def update_extension(self, upload_stream, publisher_name, extension_name, bypass_scope_check=None, **kwargs):
        """UpdateExtension.
        [Preview API] REST endpoint to update an extension.
        :param object upload_stream: Stream to upload
        :param str publisher_name: Name of the publisher
        :param str extension_name: Name of the extension
        :param bool bypass_scope_check: This parameter decides if the scope change check needs to be invoked or not
        :rtype: :class:`<PublishedExtension> <azure.devops.v5_1.gallery.models.PublishedExtension>`
        """
        route_values = {}
        if publisher_name is not None:
            route_values['publisherName'] = self._serialize.url('publisher_name', publisher_name, 'str')
        if extension_name is not None:
            route_values['extensionName'] = self._serialize.url('extension_name', extension_name, 'str')
        query_parameters = {}
        if bypass_scope_check is not None:
            query_parameters['bypassScopeCheck'] = self._serialize.query('bypass_scope_check', bypass_scope_check, 'bool')
        if "callback" in kwargs:
            callback = kwargs["callback"]
        else:
            callback = None
        content = self._client.stream_upload(upload_stream, callback=callback)
        response = self._send(http_method='PUT',
                              location_id='e11ea35a-16fe-4b80-ab11-c4cab88a0966',
                              version='5.1-preview.2',
                              route_values=route_values,
                              query_parameters=query_parameters,
                              content=content,
                              media_type='application/octet-stream')
        return self._deserialize('PublishedExtension', response)