title: Read file content from S3 bucket with boto3
body: <p>I read the filenames in my S3 bucket by doing </p>
  
  <pre><code>objs = boto3.client.list_objects(Bucket='my_bucket')
      while 'Contents' in objs.keys():
          objs_contents = objs['Contents']
          for i in range(len(objs_contents)):
              filename = objs_contents[i]['Key']
  </code></pre>
  
  <p>Now, I need to get the actual content of the file, similarly to a <code>open(filename).readlines()</code>. What is the best way?</p>