I'm testing Spock on a development machine (my laptop). Here's Spock's configuration:

environments:
  - production
  - staging
  - dev
git_push: true
commands_after:
  - 'php please clear:cache'
  # - 'php please clear:stache'

And here is the error produced:

[2018-09-21 08:05:12] dev.ERROR: Spock command exited unsuccessfully:
Command: php please clear:cache
Output: 
[Symfony\Component\Debug\Exception\FatalErrorException]               
  Default value for parameters with a class type hint can only be NULL

Error: No error  

Any ideas?