Fix incorrect WebSocket example in Python documentation

Description of Issue

The Python documentation on the Perspective website provided an incorrect WebSocket example under the Tornado section. The example had a few critical issues:

The variable table was used instead of server_table when creating a new view.
The view() method was incorrectly called on table instead of server_table.
The client_table was being created with view instead of server_view.to_json() data.

These errors would cause confusion for users trying to implement Perspective with Tornado WebSockets, as the provided code would not function as intended.

Solution

This pull request addresses the issues by correcting the example code. Here are the specific changes made:

Updated const server_view = await table.view(); to const server_view = await server_table.view(); to use the correct variable.
Modified const client_table = await worker.table(view); to const client_table = await worker.table(await server_view.to_json()); so it creates the client-side table with the correct data.

Testing the Fix

To test the fix, I set up a local Tornado server using the corrected code and verified that the WebSocket connection was established successfully and the Perspective viewer loaded and displayed data as expected.

These corrections ensure that the example provided in the documentation is accurate and functional, thus improving the reliability of the documentation and helping prevent implementation issues for future users.

finos / perspective