acrylamid check : strange error

[ghost]

Just with default installation with --mako:

[xan@argonia blog]$ acrylamid check help
usage: acrylamid check [-h] [-r] [-s SLEEP] [-w] [-j JOBS] [{W3C,links}]
acrylamid check: error: argument action: invalid choice: 'help' (choose from 'W3C', 'links')
[xan@argonia blog]$ acrylamid check
http://somenxavier.xyz/ Traceback (most recent call last):
  File "/usr/bin/acrylamid", line 9, in <module>
    load_entry_point('acrylamid==0.7.10', 'console_scripts', 'acrylamid')()
  File "/usr/lib/python3.4/site-packages/acrylamid/__init__.py", line 213, in Acryl
    tasks.collected[options.parser](conf, env, options)
  File "/usr/lib/python3.4/site-packages/acrylamid/tasks/check.py", line 142, in run
    w3c(paths, conf, warn=options.warn, sleep=options.sleep)
  File "/usr/lib/python3.4/site-packages/acrylamid/tasks/check.py", line 69, in w3c
    headers['x-w3c-validator-warnings'] + ' warns'
TypeError: unsupported operand type(s) for +: 'NoneType' and 'str'

What happens?