diff --git a/preprocessing/create_pretraining_data.py b/preprocessing/create_pretraining_data.py
index 225d2e7..a935215 100644
--- a/preprocessing/create_pretraining_data.py
+++ b/preprocessing/create_pretraining_data.py
@@ -76,13 +76,11 @@ def write_instance_to_example_file(instances, tokenizer, max_seq_length,
   for inst_index, instance in enumerate(tqdm(instances)):
     input_ids = tokenizer.convert_tokens_to_ids(instance.tokens)
     input_mask = [1] * len(input_ids)
-    segment_ids = list(instance.segment_ids)
     assert len(input_ids) <= max_seq_length
 
     while len(input_ids) < max_seq_length:
       input_ids.append(0)
       input_mask.append(0)
-      segment_ids.append(0)
 
     assert len(input_ids) == max_seq_length
     assert len(input_mask) == max_seq_length
@@ -125,8 +123,8 @@ def create_training_instances(input_files, tokenizer, max_seq_length,
   for input_file in input_files:
     print("creating instance from {}".format(input_file))
     with open(input_file, "r") as reader:
-      while True:
-        line = tokenization.convert_to_unicode(reader.readline())
+      for dirty_line in reader:
+        line = tokenization.convert_to_unicode(dirty_line)
         line = line.strip()
         tokens = tokenizer.tokenize(line)
         all_sequences.append(tokens)
@@ -137,8 +135,8 @@ def create_training_instances(input_files, tokenizer, max_seq_length,
   instances = []
   for _ in range(dupe_factor):
     for sequence_index in range(len(all_sequences)):
-      instances.extend(
-          create_instances_from_document(
+      instances.append(
+          create_instance_from_sequence(
               all_sequences, sequence_index, max_seq_length,
               masked_lm_prob, max_predictions_per_seq, vocab_residues, rng))
 
@@ -146,29 +144,24 @@ def create_training_instances(input_files, tokenizer, max_seq_length,
   return instances
 
 
-def create_instances_from_document(
+def create_instance_from_sequence(
     all_sequences, sequence_index, max_seq_length,
     masked_lm_prob, max_predictions_per_seq, vocab_residues, rng):
   """Creates `TrainingInstance`s for a single document."""
   sequence = all_sequences[sequence_index]
+ 
+  tokens = sequence[:max_seq_length]
+  tokens[0] = '[CLS]'
+  tokens[-1] = '[SEP]'
+  (tokens, masked_lm_positions,
+      masked_lm_labels) = create_masked_lm_predictions(
+  tokens, masked_lm_prob, max_predictions_per_seq, vocab_residues, rng)
+  instance = TrainingInstance(
+    tokens=tokens,
+    masked_lm_positions=masked_lm_positions,
+    masked_lm_labels=masked_lm_labels)
 
-  instances = []
-  i = 0
-  while i < len(sequence):
-    tokens = sequence[:max_seq_length]
-    tokens[0] = '[CLS]'
-    tokens[-1] = '[SEP]'
-    (tokens, masked_lm_positions,
-    masked_lm_labels) = create_masked_lm_predictions(
-        tokens, masked_lm_prob, max_predictions_per_seq, vocab_residues, rng)
-    instance = TrainingInstance(
-        tokens=tokens,
-        masked_lm_positions=masked_lm_positions,
-        masked_lm_labels=masked_lm_labels)
-    instances.append(instance)
-    i += 1
-
-  return instances
+  return instance
 
 
 MaskedLmInstance = collections.namedtuple("MaskedLmInstance",
@@ -295,7 +288,8 @@ def main():
 
     args = parser.parse_args()
 
-    tokenizer = ProteoNeMoTokenizer(args.vocab_file, args.small_vocab_file, do_upper_case=args.do_upper_case, max_len=512)
+    tokenizer = ProteoNeMoTokenizer(args.vocab_file, args.small_vocab_file, do_upper_case=args.do_upper_case, 
+      max_len=args.max_seq_length)
     
     input_files = []
     if os.path.isfile(args.input_file):
diff --git a/preprocessing/tokenization.py b/preprocessing/tokenization.py
index c80de82..be35e11 100644
--- a/preprocessing/tokenization.py
+++ b/preprocessing/tokenization.py
@@ -48,7 +48,7 @@ def convert_to_unicode(text):
 def load_vocab(vocab_file):
     """Loads a vocabulary file into a dictionary."""
     vocab = collections.OrderedDict()
-    index = 0
+    index = 1
     with open(vocab_file, "r", encoding="utf-8") as reader:
         while True:
             token = reader.readline()