--- a/docutil/dochtml.py	Mon Aug 21 20:17:19 2017 +0000
+++ b/docutil/dochtml.py	Mon Aug 21 23:22:58 2017 +0300
@@ -22,10 +22,14 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
-import wx, os, wx.html, subprocess
+import os
+import subprocess
+import wx
+import wx.html
 
 HtmlFrameOpened = []
 
+
 def OpenHtmlFrame(self, title, file, size):
         if title not in HtmlFrameOpened:
             HtmlFrameOpened.append(title)
@@ -35,15 +39,18 @@
             window.SetClientSize(size)
             window.Show()
 
+
 [ID_HTMLFRAME, ID_HTMLFRAMEHTMLCONTENT] = [wx.NewId() for _init_ctrls in range(2)]
 EVT_HTML_URL_CLICK = wx.NewId()
 
+
 class HtmlWindowUrlClick(wx.PyEvent):
     def __init__(self, linkinfo):
         wx.PyEvent.__init__(self)
         self.SetEventType(EVT_HTML_URL_CLICK)
         self.linkinfo = (linkinfo.GetHref(), linkinfo.GetTarget())
-        
+
+
 class UrlClickHtmlWindow(wx.html.HtmlWindow):
     """ HTML window that generates and OnLinkClicked event.
 
@@ -51,47 +58,48 @@
     """
     def OnLinkClicked(self, linkinfo):
         wx.PostEvent(self, HtmlWindowUrlClick(linkinfo))
-    
+
     def Bind(self, event, handler, source=None, id=wx.ID_ANY, id2=wx.ID_ANY):
         if event == HtmlWindowUrlClick:
             self.Connect(-1, -1, EVT_HTML_URL_CLICK, handler)
         else:
             wx.html.HtmlWindow.Bind(event, handler, source=source, id=id, id2=id2)
 
+
 class HtmlFrame(wx.Frame):
         def _init_ctrls(self, prnt):
             wx.Frame.__init__(self, id=ID_HTMLFRAME, name='HtmlFrame',
-                  parent=prnt, pos=wx.Point(320, 231), size=wx.Size(853, 616),
-                  style=wx.DEFAULT_FRAME_STYLE, title='')
+                              parent=prnt, pos=wx.Point(320, 231), size=wx.Size(853, 616),
+                              style=wx.DEFAULT_FRAME_STYLE, title='')
             self.SetIcon(prnt.icon)
             self.Bind(wx.EVT_CLOSE, self.OnCloseFrame)
-            
+
             self.HtmlContent = UrlClickHtmlWindow(id=ID_HTMLFRAMEHTMLCONTENT,
-                  name='HtmlContent', parent=self, pos=wx.Point(0, 0),
-                  size=wx.Size(-1, -1), style=wx.html.HW_SCROLLBAR_AUTO|wx.html.HW_NO_SELECTION)
+                                                  name='HtmlContent', parent=self, pos=wx.Point(0, 0),
+                                                  size=wx.Size(-1, -1), style=wx.html.HW_SCROLLBAR_AUTO | wx.html.HW_NO_SELECTION)
             self.HtmlContent.Bind(HtmlWindowUrlClick, self.OnLinkClick)
 
         def __init__(self, parent, opened):
             self._init_ctrls(parent)
             self.HtmlFrameOpened = opened
-            
+
         def SetHtmlCode(self, htmlcode):
             self.HtmlContent.SetPage(htmlcode)
-            
+
         def SetHtmlPage(self, htmlpage):
             self.HtmlContent.LoadPage(htmlpage)
-            
+
         def OnCloseFrame(self, event):
             self.HtmlFrameOpened.remove(self.GetTitle())
             event.Skip()
-        
+
         def OnLinkClick(self, event):
             url = event.linkinfo[0]
             try:
                 if wx.Platform == '__WXMSW__':
                     import webbrowser
                     webbrowser.open(url)
-                elif subprocess.call("firefox %s"%url, shell=True) != 0:
+                elif subprocess.call("firefox %s" % url, shell=True) != 0:
                     wx.MessageBox("""Firefox browser not found.\nPlease point your browser at :\n%s""" % url)
             except ImportError:
                 wx.MessageBox('Please point your browser at: %s' % url)