Incident Update API with Python Suds - error "java.lang.NullPointerException"

I'm trying to implement a python script for updating incidents. Here is the one:

import ssl, logging
from suds.client import Client
from suds.transport.http import HttpAuthenticated
from suds import WebFault

logging.basicConfig(level=logging.INFO)
logging.getLogger('suds.client').setLevel(logging.WARNING)

dlpServer = 'server-name'
dlpUser = 'Administrator'
dlpPass = 'secret_password'
dlpUrl = 'https://' + dlpServer + '/ProtectManager/services/v2011/incidents?wsdl'

ssl._create_default_https_context = ssl._create_unverified_context
dlpTransport = HttpAuthenticated(username = dlpUser, password = dlpPass)
dlpClient = Client(dlpUrl, transport = dlpTransport)

attrList = dlpClient.factory.create('ns3:IncidentAttributes')
attrList.dataOwner.name = "test"

batch = dlpClient.factory.create('ns3:IncidentUpdateBatch')
batch.incidentId = "4495497"
batch.batchId = "_testing"
batch.incidentAttributes = attrList

try:
    result = dlpClient.service.updateIncidents(batch)
except WebFault, e:
  print e

After executing I got the error message in a console:

ERROR:suds.client:<?xml version="1.0" encoding="UTF-8"?><SOAP-ENV:Envelope xmlns:ns0="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ns1="http://www.vontu.com/v2011/enforce/webservice/incident/schema" xmlns:ns2="http://www.vontu.com/v2011/enforce/webservice/incident/common/schema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"><SOAP-ENV:Header/><ns0:Body><ns1:incidentUpdateRequest><updateBatch><batchId>_testing</batchId><incidentId>4495497</incidentId><incidentAttributes><dataOwner><ns2:name>test</ns2:name></dataOwner></incidentAttributes></updateBatch></ns1:incidentUpdateRequest></ns0:Body></SOAP-ENV:Envelope>
Server raised fault: 'java.lang.NullPointerException'

And in the VontuManager.log I see the corresponding error message:

INFO   | jvm 1    | 2017/02/22 09:38:35 | java.lang.NullPointerException
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.vontu.enforce.webservice.log.WebServiceSOAPLoggerBase.getOperation(WebServiceSOAPLoggerBase.java:126)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.vontu.enforce.webservice.log.WebServiceSOAPLoggerBase.logMessage(WebServiceSOAPLoggerBase.java:98)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.vontu.enforce.webservice.log.WebServiceSOAPLoggerBase.handleMessage(WebServiceSOAPLoggerBase.java:58)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.vontu.enforce.webservice.log.WebServiceSOAPLoggerBase.handleMessage(WebServiceSOAPLoggerBase.java:36)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.sun.xml.ws.handler.HandlerProcessor.callHandleMessage(HandlerProcessor.java:284)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.sun.xml.ws.handler.HandlerProcessor.callHandlersRequest(HandlerProcessor.java:135)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.sun.xml.ws.handler.ServerMessageHandlerTube.callHandlersOnRequest(ServerMessageHandlerTube.java:123)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.sun.xml.ws.handler.HandlerTube.processRequest(HandlerTube.java:116)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.sun.xml.ws.api.pipe.Fiber.__doRun(Fiber.java:598)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.sun.xml.ws.api.pipe.Fiber._doRun(Fiber.java:557)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:542)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.sun.xml.ws.api.pipe.Fiber.runSync(Fiber.java:439)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.sun.xml.ws.server.WSEndpointImpl$2.process(WSEndpointImpl.java:243)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.sun.xml.ws.transport.http.HttpAdapter$HttpToolkit.handle(HttpAdapter.java:471)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.sun.xml.ws.transport.http.HttpAdapter.handle(HttpAdapter.java:244)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.sun.xml.ws.transport.http.servlet.ServletAdapter.handle(ServletAdapter.java:135)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.sun.xml.ws.transport.http.servlet.WSServletDelegate.doGet(WSServletDelegate.java:129)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.sun.xml.ws.transport.http.servlet.WSServletDelegate.doPost(WSServletDelegate.java:160)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at com.sun.xml.ws.transport.http.servlet.WSServlet.doPost(WSServlet.java:75)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
INFO   | jvm 1    | 2017/02/22 09:38:35 | 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at sun.reflect.GeneratedMethodAccessor185.invoke(Unknown Source)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at java.lang.reflect.Method.invoke(Method.java:597)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.security.SecurityUtil$1.run(SecurityUtil.java:274)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.security.SecurityUtil$1.run(SecurityUtil.java:271)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at java.security.AccessController.doPrivileged(Native Method)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at javax.security.auth.Subject.doAsPrivileged(Subject.java:517)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.security.SecurityUtil.execute(SecurityUtil.java:306)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.security.SecurityUtil.doAsPrivilege(SecurityUtil.java:166)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:299)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.core.ApplicationFilterChain.access$000(ApplicationFilterChain.java:57)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.core.ApplicationFilterChain$1.run(ApplicationFilterChain.java:193)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.core.ApplicationFilterChain$1.run(ApplicationFilterChain.java:189)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at java.security.AccessController.doPrivileged(Native Method)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at com.vontu.manager.filters.P3PHeaderFilter.doFilter(P3PHeaderFilter.java:32)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at sun.reflect.GeneratedMethodAccessor191.invoke(Unknown Source)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at java.lang.reflect.Method.invoke(Method.java:597)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.security.SecurityUtil$1.run(SecurityUtil.java:274)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.security.SecurityUtil$1.run(SecurityUtil.java:271)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at java.security.AccessController.doPrivileged(Native Method)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at javax.security.auth.Subject.doAsPrivileged(Subject.java:517)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.security.SecurityUtil.execute(SecurityUtil.java:306)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.security.SecurityUtil.doAsPrivilege(SecurityUtil.java:246)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.core.ApplicationFilterChain.access$000(ApplicationFilterChain.java:57)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.core.ApplicationFilterChain$1.run(ApplicationFilterChain.java:193)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.core.ApplicationFilterChain$1.run(ApplicationFilterChain.java:189)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at java.security.AccessController.doPrivileged(Native Method)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:581)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at com.vontu.manager.security.VontuFormAuthenticatorValve.invoke(VontuFormAuthenticatorValve.java:65)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at com.vontu.manager.security.ClientCertificateLoginValve.invoke(ClientCertificateLoginValve.java:81)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at com.vontu.manager.security.SpcSsoValve.invoke(SpcSsoValve.java:106)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at com.vontu.manager.security.IpCatcherValve.invoke(IpCatcherValve.java:73)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at com.vontu.manager.security.CharacterEncodingValve.invoke(CharacterEncodingValve.java:42)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:928)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:539)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:298)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
INFO   | jvm 1    | 2017/02/22 09:38:36 | 	at java.lang.Thread.run(Thread.java:662)

But at the same time, I can successfully fetch any incident data.

For the reference, DLP version is 11.6.2.

Any ideas?