TypeError:
wrong argument type Class (expected Module)
# (eval):311:in `extend'
# (eval):311:in `_nt_line'
# (eval):21:in `block in _nt_document'
# (eval):20:in `loop'
# (eval):20:in `_nt_document'
# /Users/gingray/.rvm/gems/ruby-2.2.2/gems/treetop-1.6.8/lib/treetop/runtime/compiled_parser.rb:18:in `parse'
# ./app/services/parser/chord_parser.rb:8:in `parse'
# ./spec/services/parser/chord_parser_spec.rb:3:in `block (2 levels) in <top (required)>'
# ./spec/services/parser/chord_parser_spec.rb:5:in `block (2 levels) in <top (required)>'
# ./spec/spec_helper.rb:36:in `block (2 levels) in <top (required)>'