I can confirm that Keras 2 doesn't work on Lesson 1. I am getting this import error:
fastai/courses/deeplearning1/nbs/utils.py in <module>()
40 from keras.layers import TimeDistributed, Activation, SimpleRNN, GRU
41 from keras.layers.core import Flatten, Dense, Dropout, Lambda
---> 42 from keras.regularizers import l2, activity_l2, l1, activity_l1
43 from keras.layers.normalization import BatchNormalization
44 from keras.optimizers import SGD, RMSprop, Adam
ImportError: cannot import name activity_l2
I am using an Ubuntu box (not on AWS), set up with install-gpu.sh. Downgrading to Keras 1.x resolves the problem:
pip install 'keras<2'
I suggest that
install-gpu.sh is changed to use Keras 1.x, like above, until all materials have been updated to Keras 2.