code: def downsample(self, percentage):
      n = int(len(self.train) * percentage)
      self.train = self.train[:n]
      n = int(len(self.test) * percentage)
      self.test = self.test[:n]
      return self
  
file_path: underthesea/examples/pos_tag/data.py
imports: from os.path import join
label_desc: Use image node_id 2 for calling the TaggedCorpus obj's underlying member method code with example usage: obj.downsample(percentage) and returns: self