code: def _truncate(self, items, length):
      for _ in range(length):
          yield next(items)
  
file_path: pytext/pytext/data/test/batch_sampler_test.py
imports: import unittest
  from pytext.data import AlternatingRandomizedBatchSampler, EvalBatchSampler, RandomizedBatchSampler, RoundRobinBatchSampler
label_desc: Use image node_id 7 for calling the BatchSamplerTest obj's underlying member method code with example usage: obj._truncate(items, length) without return types