I removed python-trezor 0.6, downloaded the current version from github and ran

sudo pip install trezor

When I attempt to launch Electrum 2.9.3 or trezorctl, I get the following error

TypeError: __init__() got an unexpected keyword argument 'syntax'

My system is running:
protobuf 3.3.0
libprotoc 2.6.1

I can recover the Electrum GUI by switching back to 0.6, but am unable to move any funds from the hardware wallet.