title: Code for Python Package OS for opening an application in Windows 10
body: <p>I am making an application which opens an app by user command. 
  It is showing "The system cannot find the file -a."</p>
  
  <p>What is the correct command for this piece of code.</p>
  
  <pre><code>if "launch" or "open" in text:
      app = text.split(" ", 1)[-1]
      self.respond("Opening " + app)
      os.system("start -a " + app + ".app")
  </code></pre>