Issues with fastai imports and torch imports in fastai v0.7 and torch v0.3.1

I am running lesson 2 code on google colab. I am using fastai v0.7 and torch v0.3.1 library. In import statements I get error whenever try to import manually or fastai library() try to import torch.as_tensor method. Also in fastai.imports import *
I get this error : module torch has no attribute float32
Please suggest how to proceed/debug.