code: def get_item3(self, i):
      self.count += 1
      return ("item3({:d})".format(i),)
  
imports: import numpy
  import unittest
  from chainercv.chainer_experimental.datasets.sliceable import GetterDataset
  from chainercv.utils import testing
label_desc: Use image node_id 5 for calling the SampleDataset obj's underlying member method code with example usage: obj.get_item3(i) and returns: str