code: function(obj) {
      var self = this
      var environmentVariables = obj[ENVIRONMENT_VARIABLES_FIELD]
      if (environmentVariables && _.size(environmentVariables) > 0) {
        _.forIn(environmentVariables, function(value, key) {
          var envVar = process.env[key]
          if (value.required && !envVar) {
            console.log("Error: Environment variable " + key + " is required.")
            // XXX: using 1 here for "general" error, but should probably allow for
            //      configuration
            self._argparser.print(self._argparser.getUsage(), 1)
          }
          if (value.private) {
            if (!process[PRIVATE_ENV_FIELD]) {
              process[PRIVATE_ENV_FIELD] = {}
            }
            process[PRIVATE_ENV_FIELD][key] = envVar
            delete process.env[key]
          }
        })
      }
    }
docs: ***************************************************************************
  @method _processEnvironmentVariables
  @description Processes any environment variables defined by "obj". This will
  sanitize ``process.env`` if an environment variable is "private" and
  fail with a usage message if a required environment variable is not
  present.
  @param {Object} obj -- The object being constructed
  @ignore