message: Update word2vec_basic.py
  Is there any time that `(data_index - span) % len(data)` is different than `(data_index + len(data) - span) % len(data)`? I couldn't find a reason to add the divisor len(data) here.
diff: @@ -149,7 +149,7 @@ def word2vec_basic(log_dir):
  buffer.append(data[data_index])
  data_index += 1
  # Backtrack a little bit to avoid skipping words in the end of a batch
  - data_index = (data_index + len(data) - span) % len(data)
  + data_index = (data_index - span) % len(data)
  return batch, labels
  batch, labels = generate_batch(batch_size=8, num_skips=2, skip_window=1)
  