code: public TOTPGenerator.Mode getMode() throws GuacamoleException {
          return environment.getProperty(TOTP_MODE, TOTPGenerator.Mode.SHA1);
      }
docs: Returns the hash algorithm that should be used to generate TOTP codes. If
  not specified, SHA1 will be used by default.
  
  @return
  The hash algorithm that should be used to generate TOTP codes.
  
  @throws GuacamoleException
  If the "totp-mode" property cannot be read from
  guacamole.properties.