wraith multi_capture command not working

[spencer95]

When calling:
wraith multi_capture /vagrant/paths-en/nodes1.yml /vagrant/paths-en/nodes2.yml

I get the error message:
ERROR: "wraith multi_capture" was called with arguments ["/vagrant/paths-en/nodes1.yml", "/vagrant/paths-en/nodes2.yml"]

It may be that I have the wrong format for the file list, but I can't see anywhere that specifies the file list format.

Issue checklist:

• [Yes ] I have validated my config file against YAML Validator to make sure it is valid YAML.

• I have run the wraith info command and pasted the output below:
  DEBUG: #################################################
  DEBUG: Command run: info
  DEBUG: Wraith version: 4.2.3
  DEBUG: Ruby version: ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-linux-gnu]
  DEBUG: ImageMagick: Version: ImageMagick 6.9.7-4 Q16 x86_64 20170114 http://www.imagemagick.org
  DEBUG: PhantomJS version: PhantomJS not installed
  DEBUG: chromedriver version: ChromeDriver 76.0.3809.126 (d80a294506b4c9d18015e755cee48f953ddc3f2f-refs/branch-heads/3809@{#1024})
  DEBUG: CasperJS version: CasperJS not installed
  DEBUG: #################################################
  Connection to 127.0.0.1 closed.

- [ Yes] I have run the command in verbose mode (by adding `verbose: true` to my config) and pasted the output below:

ERROR: "wraith multi_capture" was called with arguments ["/vagrant/paths-en/nodes1.yml", "/vagrant/paths-en/nodes2.yml"]
Usage: "wraith multi_capture [filelist]"
Connection to 127.0.0.1 closed.

• I have pasted the contents of my config file below:
  The config files work fine when wraith capture is run on them individually.