GetProcessWorkItemTypes.
        [Preview API] Returns a list of all work item types in a process.
        :param str process_id: The ID of the process
        :param str expand: Flag to determine what properties of work item type to return
        :rtype: [ProcessWorkItemType]

def get_process_work_item_types(self, process_id, expand=None):
        """GetProcessWorkItemTypes.
        [Preview API] Returns a list of all work item types in a process.
        :param str process_id: The ID of the process
        :param str expand: Flag to determine what properties of work item type to return
        :rtype: [ProcessWorkItemType]
        """
        route_values = {}
        if process_id is not None:
            route_values['processId'] = self._serialize.url('process_id', process_id, 'str')
        query_parameters = {}
        if expand is not None:
            query_parameters['$expand'] = self._serialize.query('expand', expand, 'str')
        response = self._send(http_method='GET',
                              location_id='e2e9d1a6-432d-4062-8870-bfcb8c324ad7',
                              version='5.0-preview.2',
                              route_values=route_values,
                              query_parameters=query_parameters)
        return self._deserialize('[ProcessWorkItemType]', self._unwrap_collection(response))