'LightningTemplateModel' object has no attribute '_lazy_train_dataloader'
Describe the bug
Try to run the file single_gpu_node_ddp_template.py, to test the code, but got error:
To Reproduce
Steps to reproduce the behavior:

Download folder pytorch-lightning/examples/new_project_templates/
run file: $python ingle_gpu_node_ddp_template.py$
See error

Screenshots
If applicable, add screenshots to help explain your problem.
Desktop (please complete the following information):

OS: ubuntu18
pytorch 1.2, cudatoolkit  9.2
pytorch_lgihting 0.5