diff --git a/textext.py b/textext.py
index 75b8e82..5e7ee35 100755
--- a/textext.py
+++ b/textext.py
@@ -66,23 +66,23 @@ except ImportError:
 
 USE_TK = False
 try:
-    import Tkinter as Tk
+    import tkinter as Tk
     USE_TK = True
 except ImportError:
     pass
 
 USE_WINDOWS = (platform.system() == "Windows")
 
-TEXTEXT_NS = u"http://www.iki.fi/pav/software/textext/"
-SVG_NS = u"http://www.w3.org/2000/svg"
-XLINK_NS = u"http://www.w3.org/1999/xlink"
+TEXTEXT_NS = "http://www.iki.fi/pav/software/textext/"
+SVG_NS = "http://www.w3.org/2000/svg"
+XLINK_NS = "http://www.w3.org/1999/xlink"
 
 ID_PREFIX = "textext-"
 
 NSS = {
-    u'textext': TEXTEXT_NS,
-    u'svg': SVG_NS,
-    u'xlink': XLINK_NS,
+    'textext': TEXTEXT_NS,
+    'svg': SVG_NS,
+    'xlink': XLINK_NS,
 }
 
 #------------------------------------------------------------------------------
@@ -105,9 +105,9 @@ if USE_GTK:
             window.set_title("TeX Text")
             window.set_default_size(600, 400)
     
-            label1 = gtk.Label(u"Preamble file:")
-            label2 = gtk.Label(u"Scale factor:")
-            label3 = gtk.Label(u"Text:")
+            label1 = gtk.Label("Preamble file:")
+            label2 = gtk.Label("Scale factor:")
+            label3 = gtk.Label("Text:")
 
 
             if hasattr(gtk, 'FileChooserButton'):
@@ -208,7 +208,7 @@ if USE_GTK:
             
             try:
                 self.callback(self.text, self.preamble_file, self.scale_factor)
-            except StandardError, e:
+            except Exception as e:
                 err_msg = traceback.format_exc()
                 dlg = gtk.Dialog("Textext Error", self._window, 
                                  gtk.DIALOG_MODAL)
@@ -340,7 +340,7 @@ class TexText(inkex.Effect):
                 conv_cls.available()
                 converter_cls = conv_cls
                 break
-            except StandardError, e:
+            except Exception as e:
                 converter_errors.append("%s: %s" % (conv_cls.__name__, str(e)))
         
         if not converter_cls:
@@ -378,7 +378,7 @@ class TexText(inkex.Effect):
         if not text:
             return
 
-        if isinstance(text, unicode):
+        if isinstance(text, str):
             text = text.encode('utf-8')
         
         # Convert
@@ -505,16 +505,16 @@ class Settings(object):
     
     def load(self):
         if USE_WINDOWS:
-            import _winreg
+            import winreg
             try:
-                key = _winreg.OpenKey(_winreg.HKEY_CURRENT_USER, self.keyname)
+                key = winreg.OpenKey(winreg.HKEY_CURRENT_USER, self.keyname)
             except:
                 return
             try:
                 self.values = {}
                 for j in range(1000):
                     try:
-                        name, data, dtype = _winreg.EnumValue(key, j)
+                        name, data, dtype = winreg.EnumValue(key, j)
                     except EnvironmentError:
                         break
                     self.values[name] = str(data)
@@ -536,15 +536,15 @@ class Settings(object):
     
     def save(self):
         if USE_WINDOWS:
-            import _winreg
+            import winreg
             try:
-                key = _winreg.OpenKey(_winreg.HKEY_CURRENT_USER, self.keyname,
-                                      sam=_winreg.KEY_SET_VALUE | _winreg.KEY_WRITE)
+                key = winreg.OpenKey(winreg.HKEY_CURRENT_USER, self.keyname,
+                                      sam=winreg.KEY_SET_VALUE | winreg.KEY_WRITE)
             except:
-                key = _winreg.CreateKey(_winreg.HKEY_CURRENT_USER, self.keyname)
+                key = winreg.CreateKey(winreg.HKEY_CURRENT_USER, self.keyname)
             try:
-                for k, v in self.values.iteritems():
-                    _winreg.SetValueEx(key, str(k), 0, _winreg.REG_SZ, str(v))
+                for k, v in self.values.items():
+                    winreg.SetValueEx(key, str(k), 0, winreg.REG_SZ, str(v))
             finally:
                 key.Close()
         else:
@@ -555,7 +555,7 @@ class Settings(object):
             f = open(self.filename, 'w')
             try:
                 data = '\n'.join(["%s=%s" % (k,v)
-                                  for k,v in self.values.iteritems()])
+                                  for k,v in self.values.items()])
                 f.write(data)
             finally:
                 f.close()
@@ -588,7 +588,7 @@ try:
                                  stderr=subprocess.PIPE,
                                  stdin=subprocess.PIPE)
             out, err = p.communicate()
-        except OSError, e:
+        except OSError as e:
             raise RuntimeError("Command %s failed: %s" % (' '.join(cmd), e))
         
         if ok_return_value is not None and p.returncode != ok_return_value:
@@ -614,7 +614,7 @@ except ImportError:
             p.tochild.close()
             returncode = p.wait() >> 8
             out = p.fromchild.read()
-        except OSError, e:
+        except OSError as e:
             raise RuntimeError("Command %s failed: %s" % (' '.join(cmd), e))
         
         if ok_return_value is not None and returncode != ok_return_value:
@@ -787,7 +787,7 @@ class PdfConverterBase(LatexConverterBase):
         if node.tag.startswith(svg):
             node.tag = node.tag[len(svg):]
         
-        for key in node.attrib.keys():
+        for key in list(node.attrib.keys()):
             if key.startswith(svg):
                 new_key = key[len(svg):]
                 node.attrib[new_key] = node.attrib[key]
-- 
2.25.2