Error while trying to run NiftyNet quick start command
Please Install tensorflow using this command
pip install tensorflow
After that install nifty net using below command 
'''
pip install niftynet
'''
reinstall the python
'''
pip install python
'''
if the problem is still than please mentioned your problem in more details
please make sure your environment variable is set before executing the command from niftynet page.
I'm trying out NiftyNet and got stuck at the first step.
Trying to run the quickstart command

python net_download.py dense_vnet_abdominal_ct_model_zoo
  python net_segment.py inference -c  ~/niftynet/extensions/dense_vnet_abdominal_ct/config.ini

gives me 

KeyError: "Registering two gradient with name 'FloorMod' !(Previous registration was in _find_and_load_unlocked :955)"

Could any one help? I'm using Ubuntu 16.04 with Nvidia GPU. Tried tensorflow:1.4.1-py3 docker image, Anaconda with CPU version of tensorflow 
and native python with CPU version of tensorflow and I get the same error.
I'm pretty sure it's something I did wrong because I get the same error from those different environment but I'm not sure what...
Thanks!