Client crash on ubuntu 17.04

tmh@tmhn:~/.sovrin$ sovrin
Loading module /usr/local/lib/python3.5/dist-packages/config/config-crypto-example1.py
Module loaded.
Traceback (most recent call last):
 File "/usr/local/bin/sovrin", line 78, in <module>
 run_cli()
 File "/usr/local/bin/sovrin", line 53, in run_cli
 withNode=withNode
 File "/usr/local/lib/python3.5/dist-packages/sovrin_client/cli/cli.py", line 111, in __init__
 super().__init__(*args, **kwargs)
 File "/usr/local/lib/python3.5/dist-packages/plenum/cli/cli.py", line 265, in __init__
 self.print("\n{}-CLI (c) 2017 Evernym, Inc.".format(self.properName))
 File "/usr/local/lib/python3.5/dist-packages/sovrin_client/cli/cli.py", line 1703, in print
 super().print(msg, token=token, newline=newline)
 File "/usr/local/lib/python3.5/dist-packages/plenum/cli/cli.py", line 622, in print
 self.cli.run_in_terminal(part)
 File "/usr/lib/python3/dist-packages/prompt_toolkit/interface.py", line 621, in run_in_terminal
 result = func()
 File "/usr/lib/python3/dist-packages/prompt_toolkit/interface.py", line 770, in print_tokens
 print_tokens(self.output, tokens, style or self.application.style)
 File "/usr/lib/python3/dist-packages/prompt_toolkit/renderer.py", line 515, in print_tokens
 attrs = attrs_for_token[token]
 File "/usr/lib/python3/dist-packages/prompt_toolkit/renderer.py", line 219, in __missing__
 result = self.get_style_for_token(token)
 File "/usr/lib/python3/dist-packages/prompt_toolkit/styles/from_dict.py", line 143, in get_attrs_for_token
 for token in split_token_in_parts(token):
 File "/usr/lib/python3/dist-packages/prompt_toolkit/styles/utils.py", line 17, in split_token_in_parts
 for part in token + (':', ):
TypeError: unsupported operand type(s) for +: 'NoneType' and 'tuple'