title: 'string' has incorrect type (expected str, got spacy.tokens.doc.Doc)
body: <p>I have a dataframe:</p>
  
  <pre><code>train_review = train['review']
  train_review
  </code></pre>
  
  <p>It looks like:</p>
  
  <pre><code>0      With all this stuff going down at the moment w...
  1      \The Classic War of the Worlds\" by Timothy Hi...
  2      The film starts with a manager (Nicholas Bell)...
  3      It must be assumed that those who praised this...
  4      Superbly trashy and wondrously unpretentious 8...
  </code></pre>
  
  <p>I add the tokens into a string:</p>
  
  <pre><code>train_review = train['review']
  train_token = ''
  for i in train['review']:
     train_token +=i
  </code></pre>
  
  <p>What I want is to tokenize the reviews using Spacy.
  Here is what I tried, but I get the following error: </p>
  
  <blockquote>
    <p>Argument 'string' has incorrect type (expected str, got
    spacy.tokens.doc.Doc)</p>
  </blockquote>
  
  <p>How can I solve that? Thanks in advance!</p>