CreateField.
        [Preview API] Create a new field.
        :param :class:`<WorkItemField> <azure.devops.v5_1.work_item_tracking.models.WorkItemField>` work_item_field: New field definition
        :param str project: Project ID or project name
        :rtype: :class:`<WorkItemField> <azure.devops.v5_1.work-item-tracking.models.WorkItemField>`

def create_field(self, work_item_field, project=None):
        """CreateField.
        [Preview API] Create a new field.
        :param :class:`<WorkItemField> <azure.devops.v5_1.work_item_tracking.models.WorkItemField>` work_item_field: New field definition
        :param str project: Project ID or project name
        :rtype: :class:`<WorkItemField> <azure.devops.v5_1.work-item-tracking.models.WorkItemField>`
        """
        route_values = {}
        if project is not None:
            route_values['project'] = self._serialize.url('project', project, 'str')
        content = self._serialize.body(work_item_field, 'WorkItemField')
        response = self._send(http_method='POST',
                              location_id='b51fd764-e5c2-4b9b-aaf7-3395cf4bdd94',
                              version='5.1-preview.2',
                              route_values=route_values,
                              content=content)
        return self._deserialize('WorkItemField', response)