new_contents: from mobileclick.methods import BaseRankingMethod
  
  class YourRankingMethod(BaseRankingMethod):
      def init(self, tasks):
          '''
          Initialization
  
          `tasks` is a list of Task instances.
          Task.query: Query
          Task.iunits: a list of Iunit instances
          Task.indices: a list of Index instances
  
          Query:
          Query.qid: Query ID
          Query.body: string of the query
  
          Iunit:
          Iunit.qid: Query ID
          Iunit.uid: iUnit ID
          Iunit.body: string of the iUnit
  
          Index (index information of a webpage in the provided document collection):
          Index.qid: Query ID
          Index.filepath: filepath of an HTML file
          Index.rank: rank in a search engine result page
          Index.title: webpage title
          Index.url: webpage url
          Index.body: summary of the webpage
          '''
  
      def rank(self, task):
          '''
          Output ranked pairs of an iUnits and a score
  
          e.g. Random ranking method
          return [(i, 0) for i in task.iunits]
          '''
          return [(i, 0) for i in task.iunits]
  
  if __name__ == '__main__':
      from mobileclick import Task
      tasks = Task.read(
          "data/MC2-training/en/1C2-E-queries.tsv",
          "data/MC2-training/en/1C2-E-iunits.tsv",
          "data/MC2-training-documents/1C2-E.INDX",
          "data/MC2-training-documents/1C2-E.HTML")
      method = YourRankingMethod()
      run = method.generate_run("YourRun", "This is your run", tasks)
      run.save('./')
  
subject: Add example for ranking