Can't show calendar for month of December

[electrodude]

calrom -m 12 fails with the following error:

Traceback (most recent call last):
        7: from /home/$USER/.gem/ruby/2.5.0/bin/calrom:23:in `<main>'
        6: from /home/$USER/.gem/ruby/2.5.0/bin/calrom:23:in `load'
        5: from /home/$USER/.gem/ruby/2.5.0/gems/calrom-0.1.0/exe/calrom:7:in `<top (required)>'
        4: from /home/$USER/.gem/ruby/2.5.0/gems/calrom-0.1.0/lib/calrom/cli.rb:4:in `call'
        3: from /home/$USER/.gem/ruby/2.5.0/gems/calrom-0.1.0/lib/calrom/option_parser.rb:45:in `call'
        2: from /home/$USER/.gem/ruby/2.5.0/gems/calrom-0.1.0/lib/calrom/option_parser.rb:45:in `new'
        1: from /home/$USER/.gem/ruby/2.5.0/gems/calrom-0.1.0/lib/calrom/date_range.rb:17:in `initialize'
/home/$USER/.gem/ruby/2.5.0/gems/calrom-0.1.0/lib/calrom/date_range.rb:17:in `new': invalid date (ArgumentError)

(wherein I replaced my username with $USER)

The same thing happens if you also specify a year, e.g. calrom -m 12 2021.

[igneus]

Thank you very much for reporting. I confirm I reproduced the error. It turned out it's been fixed in master for some time (commit d872f42). I will release a new version of the gem to Rubygems in near future.

[igneus]

Fixed in 0.2.0 which was just released to Rubygems.