code: function revert (moduleName) {
    if (moduleName) {
      console.log('reverting module', JSON.stringify(moduleName))
    }
  
    var toCheck = getDependenciesToCheck({}, moduleName)
    debug('need to check')
    debug(toCheck)
  
    var installPromises = toCheck.map(function (info) {
      la(isRevertInfo(info), 'invalid revert info', info)
      return installModule.bind(null, {
        name: info.name,
        version: info.version,
        tldr: false
      })
    })
    return installPromises.reduce(q.when, q())
  }
docs: returns promise