# File lib/mongoid/extensions/hash/criteria_helpers.rb, line 17
        def expand_complex_criteria
          {}.tap do |hsh|
            each_pair do |k,v|
              if k.respond_to?(:key) && k.respond_to?(:to_mongo_query)
                hsh[k.key] ||= {}
                hsh[k.key].merge!(k.to_mongo_query(v))
              else
                hsh[k] = v
              end
            end
          end
        end