title: unable to download the pipeline provided by spark-nlp library
body: <p>i am unable to use the predefined pipeline "recognize_entities_dl" provided by the spark-nlp library </p>
  
  <p>i tried installing different versions of pyspark and spark-nlp library</p>
  
  <pre><code>import sparknlp
  from sparknlp.pretrained import PretrainedPipeline
  
  #create or get Spark Session
  
  spark = sparknlp.start()
  
  sparknlp.version()
  spark.version
  
  #download, load, and annotate a text by pre-trained pipeline
  
  pipeline = PretrainedPipeline('recognize_entities_dl', lang='en')
  result = pipeline.annotate('Harry Potter is a great movie')
  
  2.1.0
  recognize_entities_dl download started this may take some time.
  </code></pre>
  
  <pre><code>---------------------------------------------------------------------------
  AttributeError                            Traceback (most recent call last)
  &lt;ipython-input-13-b71a0f77e93a&gt; in &lt;module&gt;
       11 #download, load, and annotate a text by pre-trained pipeline
       12 
  ---&gt; 13 pipeline = PretrainedPipeline('recognize_entities_dl', 'en')
       14 result = pipeline.annotate('Harry Potter is a great movie')
  
  d:\python36\lib\site-packages\sparknlp\pretrained.py in __init__(self, name, lang, remote_loc)
       89 
       90     def __init__(self, name, lang='en', remote_loc=None):
  ---&gt; 91         self.model = ResourceDownloader().downloadPipeline(name, lang, remote_loc)
       92         self.light_model = LightPipeline(self.model)
       93 
  
  d:\python36\lib\site-packages\sparknlp\pretrained.py in downloadPipeline(name, language, remote_loc)
       50     def downloadPipeline(name, language, remote_loc=None):
       51         print(name + " download started this may take some time.")
  ---&gt; 52         file_size = _internal._GetResourceSize(name, language, remote_loc).apply()
       53         if file_size == "-1":
       54             print("Can not find the model to download please check the name!")
  
  AttributeError: module 'sparknlp.internal' has no attribute '_GetResourceSize'
  </code></pre>