title: Why do I receive FileNotFoundError: [Errno 2] No such file or directory: '/sbin/iwlist'
body: <p>Using the following Python code:</p>
  
  <pre><code>&gt;&gt;&gt; from wifi import Cell, Scheme
  &gt;&gt;&gt; Cell.all('wlan0')
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/usr/local/lib/python3.5/site-packages/wifi/scan.py", line 39, in all
      stderr=subprocess.STDOUT)
  File"/usr/local/Cellar/python3/3.5.0/Frameworks/Python.framework/Versions/3.5/lib/python3.5/subprocess.py", line 629, in check_output
  **kwargs).stdout
    File "/usr/local/Cellar/python3/3.5.0/Frameworks/Python.framework/Versions/3.5/lib/python3.5/subprocess.py", line 696, in run
  with Popen(*popenargs, **kwargs) as process:
     File "/usr/local/Cellar/python3/3.5.0/Frameworks/Python.framework/Versions/3.5/lib/python3.5/subprocess.py", line 950, in __init__
  restore_signals, start_new_session)
    File "/usr/local/Cellar/python3/3.5.0/Frameworks/Python.framework/Versions/3.5/lib/python3.5/subprocess.py", line 1540, in _execute_child
  raise child_exception_type(errno_num, err_msg) 
  FileNotFoundError: [Errno 2] No such file or directory: '/sbin/iwlist'
  </code></pre>
  
  <p>Why am I getting the error message <code>FileNotFoundError: [Errno 2] No such file or directory: '/sbin/iwlist'?</code></p>