title: pywinauto TypeError: item 2 in _argtypes_ passes a union by value, which is unsupported
body: <p>I'm using pywinauto.</p>
  <p>Python 3.7.6
  pywinauto 0.6.8</p>
  <p>I have no issue import pywinauto module,but have following issue:</p>
  <p>code:</p>
  <pre><code>from pywinauto.application import Application
  app = Application(backend=&quot;uia&quot;).start(&quot;thinkorswim.exe&quot;)
  </code></pre>
  <p>result:</p>
  <pre><code>Traceback (most recent call last):
    File &quot;C:\Users\willi\AppData\Local\Programs\Python\Python37\lib\ctypes\__init__.py&quot;, line 121, in WINFUNCTYPE
      return _win_functype_cache[(restype, argtypes, flags)]
  KeyError: (&lt;class 'ctypes.HRESULT'&gt;, (&lt;class 'ctypes.c_long'&gt;, &lt;class 'comtypes.automation.tagVARIANT'&gt;, &lt;class 'comtypes.LP_POINTER(IUIAutomationCondition)'&gt;), 0)
  
  During handling of the above exception, another exception occurred:
  
      prototype = WINFUNCTYPE(restype, *argtypes)
    File &quot;C:\Users\willi\AppData\Local\Programs\Python\Python37\lib\ctypes\__init__.py&quot;, line 123, in WINFUNCTYPE
      class WinFunctionType(_CFuncPtr):
  TypeError: item 2 in _argtypes_ passes a union by value, which is unsupported.
  </code></pre>
  <p>Any friend can help?</p>