# File lib/pdf/reader/object_hash.rb, line 104
    def deref!(key)
      case object = deref(key)
      when Hash
        {}.tap { |hash|
          object.each do |k, value|
            hash[k] = deref!(value)
          end
        }
      when PDF::Reader::Stream
        object.hash = deref!(object.hash)
        object
      when Array
        object.map { |value| deref!(value) }
      else
        object
      end
    end