NoMethodError during execution from default branch

I ran /opt/gitlab/embedded/bin/git clone --recursive https://gitlab.com/gitlab-com/support/toolbox/gitlabsos.git && cd gitlabsos as described in the documentation and afterwards execute the script:

.sudo /opt/gitlab/embedded/bin/ruby ./gitlabsos.rb

sudo /opt/gitlab/embedded/bin/ruby ./gitlabsos.rb
Traceback (most recent call last):
	4: from ./gitlabsos.rb:403:in `<main>'
	3: from ./gitlabsos.rb:403:in `new'
	2: from ./gitlabsos.rb:329:in `initialize'
	1: from ./gitlabsos.rb:301:in `parse'
./gitlabsos.rb:308:in `ensure_valid_dates': undefined method `>' for nil:NilClass (NoMethodError)

Can someone support me with that?