UpdateStateDefinition.
        [Preview API] Updates a given state definition in the work item type of the process.
        :param :class:`<WorkItemStateInputModel> <azure.devops.v5_0.work_item_tracking_process.models.WorkItemStateInputModel>` state_model:
        :param str process_id: ID of the process
        :param str wit_ref_name: The reference name of the work item type
        :param str state_id: ID of the state
        :rtype: :class:`<WorkItemStateResultModel> <azure.devops.v5_0.work_item_tracking_process.models.WorkItemStateResultModel>`

def update_state_definition(self, state_model, process_id, wit_ref_name, state_id):
        """UpdateStateDefinition.
        [Preview API] Updates a given state definition in the work item type of the process.
        :param :class:`<WorkItemStateInputModel> <azure.devops.v5_0.work_item_tracking_process.models.WorkItemStateInputModel>` state_model:
        :param str process_id: ID of the process
        :param str wit_ref_name: The reference name of the work item type
        :param str state_id: ID of the state
        :rtype: :class:`<WorkItemStateResultModel> <azure.devops.v5_0.work_item_tracking_process.models.WorkItemStateResultModel>`
        """
        route_values = {}
        if process_id is not None:
            route_values['processId'] = self._serialize.url('process_id', process_id, 'str')
        if wit_ref_name is not None:
            route_values['witRefName'] = self._serialize.url('wit_ref_name', wit_ref_name, 'str')
        if state_id is not None:
            route_values['stateId'] = self._serialize.url('state_id', state_id, 'str')
        content = self._serialize.body(state_model, 'WorkItemStateInputModel')
        response = self._send(http_method='PATCH',
                              location_id='31015d57-2dff-4a46-adb3-2fb4ee3dcec9',
                              version='5.0-preview.1',
                              route_values=route_values,
                              content=content)
        return self._deserialize('WorkItemStateResultModel', response)