anchor.diff:  
         user = mkOption {
           default = "tss";
  +        type = types.string;
           description = "User account under which tcsd runs.";
         };
   
         group = mkOption {
           default = "tss";
  +        type = types.string;
           description = "Group account under which tcsd runs.";
         };
   
         stateDir = mkOption {
   	default = "/var/lib/tpm";
  +        type = types.path;
   	description = ''
             The location of the system persistent storage file.
             The system persistent storage file holds keys and data across
  
positive.code: 
        enable = mkOption {
          default = false;
          description = ''
            Whether to enable tcsd, a Trusted Computing management service
            that provides TCG Software Stack (TSS).  The tcsd daemon is
  
negative.code: 
        platformCred = mkOption {
          default = "${cfg.stateDir}/platform.cert";
          type = types.path;
          description = ''
  	  Path to the platform credential for your TPM. Your TPM
            manufacturer may have provided you with a set of credentials
  