How can I send a .wav file from a Processing client to a Python server?

Processing Libraries
1

Hello.
As stated in the header, i need to send a file .wav (but i think any method is suitable for any file) from a processing client to a python server which processes the file and sends it back to the processing client.
Up to now this is my very simple code which i took from a demo found on the processing website:

import processing.net.*;
import java.io.FilenameFilter;

String[] filenames;
String fullPath = "C:\\Users/aless/Desktop/client_server_prova/Client_processing/client_processing/file_audio";

Client myClient;
     
void setup() { 
    size(200, 200);
    filenames = loadFilenames(fullPath);
    
    /* Connect to the local machine at port 50007
     *  (or whichever port you choose to run the
     *  server on).
     * This example will not run if you haven't
     *  previously started a server on this port.
     */
    myClient = new Client(this, "127.0.0.1", 50007);
    
    myClient.write(filenames[0]);
    
    // DEBUG
    //myClient.write("Paging Python!");    
    //print(filenames[0]);
    // FINE DEBUG
} 
     
     
void draw() { 
    //myClient.write("Paging Python!"); // send whatever you need to send here
    
} 


String[] loadFilenames(String path) {
  File folder = new File(path);
  FilenameFilter filenameFilter = new FilenameFilter() {
    public boolean accept(File dir, String name) {
      return name.toLowerCase().endsWith(".wav");//|| name.toLowerCase().endsWith(".mp4"); // change this to any extension you want
    }
  };
  return folder.list(filenameFilter);
}

the “filenames” stuff is a failed attempt i made.
If anyone could help me i would be very grateful.
Thank you very much.