当我在Rails项目中使用Candy时，我收到以下错误。真的是语法错误吗？
=> Ctrl-C to shutdown server
Exiting
/usr/lib/ruby/gems/1.8/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:239:in `require': /home/waleed/.bundler/ruby/1.8/candy-daa2670a71e3/lib/candy/array.rb:56: syntax error, unexpected ':', expecting kEND (SyntaxError)
...lection.find_and_modify query: {"_id" => @__candy_parent.id}...
^
/home/waleed/.bundler/ruby/1.8/candy-daa2670a71e3/lib/candy/array.rb:56: syntax error, unexpected ',', expecting kEND
...{"_id" => @__candy_parent.id}, update: {'$pop' => {@__candy_...
^
/home/waleed/.bundler/ruby/1.8/candy-daa2670a71e3/lib/candy/array.rb:56: syntax error, unexpected ',', expecting kEND
... {@__candy_parent_key => -1}}, new: false
^
from /usr/lib/ruby/gems/1.8/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:239:in `require'
from /usr/lib/ruby/gems/1.8/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:225:in `load_dependency'
from /usr/lib/ruby/gems/1.8/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:596:in `new_constants_in'
from /usr/lib/ruby/gems/1.8/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:225:in `load_dependency'
from /usr/lib/ruby/gems/1.8/gems/activesupport-3.0.3/lib/active_support/dependencies.rb:239:in `require'
from /home/waleed/.bundler/ruby/1.8/candy-daa2670a71e3/lib/candy/piece.rb:1
任何想法为什么？