title: How to install BigBirdTokenizer for NLP?
body: <p>When I try to install BigBirdTokenizer I get the
  Following error</p>
  <pre><code>AttributeError                            Traceback (most recent call last)
  &lt;ipython-input-12-c81eaf9abd32&gt; in &lt;module&gt;()
  ----&gt; 1 from summarizer import Summarizer
        2 f = open(&quot;macineLearning&quot;,&quot;r&quot;)
        3 full_text = f.read()
        4 model = Summarizer()
        5 result = model(full_text, min_length=60, max_length = 500 , ratio = 0.4)
  
  4 frames
  /usr/local/lib/python3.7/dist-packages/summarizer/__init__.py in &lt;module&gt;()
  ----&gt; 1 from summarizer.model_processors import Summarizer, TransformerSummarizer
  
  /usr/local/lib/python3.7/dist-packages/summarizer/model_processors.py in &lt;module&gt;()
        2 
        3 import numpy as np
  ----&gt; 4 from transformers import *
        5 
        6 from summarizer.bert_parent import BertParent
  
  /usr/local/lib/python3.7/dist-packages/transformers/__init__.py in __getattr__(self, name)
  
  /usr/local/lib/python3.7/dist-packages/transformers/file_utils.py in __getattr__(self, name)
  
  /usr/local/lib/python3.7/dist-packages/transformers/file_utils.py in __getattr__(self, name)
  
  AttributeError: module transformers.models.big_bird has no attribute BigBirdTokenizer
  </code></pre>
  <p>I am doing this [error on first line of code below]</p>
  <pre><code>from summarizer import Summarizer
  f = open(&quot;macineLearning&quot;,&quot;r&quot;)
  full_text = f.read()
  model = Summarizer()
  result = model(full_text, min_length=60, max_length = 500 , ratio = 0.4)
  summarized_text = ''.join(result)
  print (summarized_text)
  </code></pre>
  <p>I've also installed:</p>
  <pre><code>!pip install gensim
  !pip install git+https://github.com/boudinfl/pke.git
  !python -m spacy download en
  !pip install bert-extractive-summarizer --upgrade --force-reinstall
  !pip install spacy==2.1.3 --upgrade --force-reinstall
  !pip install -U nltk
  !pip install -U pywsd
  import nltk
  nltk.download('stopwords')
  nltk.download('popular')
  !pip install sentencepiece
  !pip install BigBirdTokenizer
  !pip install sentence-transformers==0.2.5.1
  !pip install transformers==2.6.0
  </code></pre>
  <p>But the BigBirdTokenizer always seems to fail. I'm quite new to NLP but would like to understand why the issue occurs.</p>