title: Can't read redis python client messages from redis-cli
body: <p>I am publishing messages to a Redis broker from Python. </p>
  
  <p>Subscribe to "test_key" from redis-cli:</p>
  
  <pre><code># Run the server
  redis-server
  
  # In new instance, run the cli
  redis-cli
  
  # Subscribe to the key
  SUBSCRIBE test_key
  </code></pre>
  
  <p>In Python:</p>
  
  <p>version of the redis client: redis==3.4.1</p>
  
  <pre class="lang-py prettyprint-override"><code>import redis
  redis_connection = redis.Redis()  # basic conf: localhost, port 6379, db 0
  redis_connection.set("test_key", "Hello Redis")
  
  # If I run redis_connection.get("test_key")
  b'Hello Redis'
  </code></pre>
  
  <p><strong>My question</strong>: While I can get my messages from the Python environment, absolutely no messages are showing in the redis-cli terminal. What did I do wrong? </p>