    # File lib/memcache.rb, line 107
      def get(keys, opts = {})
        raise 'opts must be hash' unless opts.instance_of?(Hash)

        if keys.instance_of?(Array)
          keys = keys.collect {|key| key.to_s}
          multi_get(keys, opts)
        else
          key = keys.to_s
          if opts[:expiry]
            value = server(key).gets(key)
            cas(key, value, :raw => true, :cas => value.memcache_cas, :expiry => opts[:expiry]) if value
          else
            value = server(key).get(key, opts[:cas])
          end

          return backup.get(key, opts) if backup and value.nil?
          opts[:raw] ? value : unmarshal(value, key)
        end
      end