title: pyautocad gives ungooglable error
body: <blockquote>
    <p>OSError: [WinError -2147221005] Invalid class string</p>
  </blockquote>
  
  <p>full traceback</p>
  
  <pre><code>During handling of the above exception, another exception occurred:
  
  Traceback (most recent call last):
    File "C:/Users/MONSTR/Desktop/Ванжые/Yusuf bey/GUI/test1.py", line 10, in &lt;module&gt;
      for text in acad.iter_objects('Text'):
    File "C:\Users\MONSTR\AppData\Local\Programs\Python\Python36\lib\site-packages\pyautocad\api.py", line 111, in iter_objects
      block = self.doc.ActiveLayout.Block
    File "C:\Users\MONSTR\AppData\Local\Programs\Python\Python36\lib\site-packages\pyautocad\api.py", line 74, in doc
      return self.app.ActiveDocument
    File "C:\Users\MONSTR\AppData\Local\Programs\Python\Python36\lib\site-packages\pyautocad\api.py", line 67, in app
      self._app = comtypes.client.CreateObject('AutoCAD.Application', dynamic=True)
    File "C:\Users\MONSTR\AppData\Local\Programs\Python\Python36\lib\site-packages\comtypes\client\__init__.py", line 227, in CreateObject
      clsid = comtypes.GUID.from_progid(progid)
    File "C:\Users\MONSTR\AppData\Local\Programs\Python\Python36\lib\site-packages\comtypes\GUID.py", line 78, in from_progid
      _CLSIDFromProgID(str(progid), byref(inst))
    File "_ctypes/callproc.c", line 918, in GetResult
  OSError: [WinError -2147221005] Invalid class string
  </code></pre>
  
  <p>I get this error when I am trying to compile this code from <a href="https://pypi.python.org/pypi/pyautocad/" rel="nofollow noreferrer">here</a></p>
  
  <pre><code>from pyautocad import Autocad, APoint
  
  acad = Autocad()
  acad.prompt("Hello, Autocad from Python\n")
  print(acad.doc.Name)
  
  p1 = APoint(0, 0)
  p2 = APoint(50, 25)
  for i in range(5):
      text = acad.model.AddText('Hi %s!' % i, p1, 2.5)
      acad.model.AddLine(p1, p2)
      acad.model.AddCircle(p1, 10)
      p1.y += 10
  
  dp = APoint(10, 0)
  for text in acad.iter_objects('Text'):
      print('text: %s at: %s' % (text.TextString, text.InsertionPoint))
      text.InsertionPoint = APoint(text.InsertionPoint) + dp
  
  for obj in acad.iter_objects(['Circle', 'Line']):
      print(obj.ObjectName)
  </code></pre>
  
  <p>After few hours on google, I decided to wonder here<br>
  What can be the reason ?</p>