title: Python Error: AttributeError: __enter__
body: <p>I receive the attribute error when I try to run the code. </p>
  
  <pre><code>    with ParamExample(URI) as pe:
      with MotionCommander(pe, default_height=0.3)as mc:
  </code></pre>
  
  <p>This is where the error occurs. </p>
  
  <pre><code>Traceback (most recent call last):
  File "test44.py", line 156, in &lt;module&gt;
  with ParamExample(URI) as pe:
  AttributeError: __enter__
  </code></pre>
  
  <p>That is the traceback that I receive in my terminal. 
  If you need to see more of my code, please let me know. 
  Any help is appreciated, thank you! </p>