public function b2_delete_file_version($api_url, $auth_token, $file_id, $file_name)
        {
            $call_url   = $api_url."/b2api/v1/b2_delete_file_version";
            $auth_token = $auth_token; // Obtained from the b2_authorize_account call
            $file_id    = $file_id; // The ID of the file you want to delete
            $file_name  = $file_name; // The file name of the file you want to delete

            // Add POST fields
            $data = array(
                "fileId"   => $file_id, 
                "fileName" => $file_name
            );

            // Add headers
            $headers = array(
                "Authorization: {$auth_token}"
            );

            $result = b2_call($call_url, $headers, $data);
            return $result; // Return the result
        }