# File lib/aws/dynamo_db/client.rb, line 32
      def initialize *args

        super

        # If the signer does not provide a session token, then we will
        # replace it with another signer that manages an AWS STS session.
        # This session will auto renew whenever it has expired and will
        # be shared across threads.
        if config.signer.session_token.nil?
          @signer = Core::SessionSigner.for(config) 
        end

      end