diff --git a/wxPython/contrib/xrc/_xrcextras.py b/wxPython/contrib/xrc/_xrcextras.py
index c4f42b0cba..9562aea2eb 100644
--- a/wxPython/contrib/xrc/_xrcextras.py
+++ b/wxPython/contrib/xrc/_xrcextras.py
@@ -14,7 +14,7 @@ wx.wxXmlNodePtr = wxXmlNodePtr
 
 def _my_import(name):
     mod = __import__(name)
-    components = string.split(name, '.')
+    components = name.split('.')
     for comp in components[1:]:
         mod = getattr(mod, comp)
     return mod
diff --git a/wxPython/contrib/xrc/xrc.py b/wxPython/contrib/xrc/xrc.py
index 78e100476c..11f9e49b44 100644
--- a/wxPython/contrib/xrc/xrc.py
+++ b/wxPython/contrib/xrc/xrc.py
@@ -551,7 +551,7 @@ wx.wxXmlNodePtr = wxXmlNodePtr
 
 def _my_import(name):
     mod = __import__(name)
-    components = string.split(name, '.')
+    components = name.split('.')
     for comp in components[1:]:
         mod = getattr(mod, comp)
     return mod
diff --git a/wxPython/src/filesys.i b/wxPython/src/filesys.i
index a2732f058f..69d782e325 100644
--- a/wxPython/src/filesys.i
+++ b/wxPython/src/filesys.i
@@ -33,7 +33,6 @@
 %import streams.i
 
 %pragma(python) code = "import wx"
-%pragma(python) code = "import string"
 
 //---------------------------------------------------------------------------
 
diff --git a/wxPython/src/sizers.i b/wxPython/src/sizers.i
index 7351d910d2..094a534be5 100644
--- a/wxPython/src/sizers.i
+++ b/wxPython/src/sizers.i
@@ -30,7 +30,6 @@
 %import controls.i
 
 %pragma(python) code = "import wx"
-%pragma(python) code = "import string"
 
 //---------------------------------------------------------------------------
 
@@ -175,7 +174,7 @@ public:
     def Add(self, *args, **kw):
         if type(args[0]) == type(1):
             apply(self.AddSpacer, args, kw)
-        elif string.find(args[0].this, 'Sizer') != -1:
+        elif isinstance(args[0], wxSizerPtr):
             apply(self.AddSizer, args, kw)
         else:
             apply(self.AddWindow, args, kw)
@@ -183,7 +182,7 @@ public:
     def Insert(self, *args, **kw):
         if type(args[1]) == type(1):
             apply(self.InsertSpacer, args, kw)
-        elif string.find(args[1].this, 'Sizer') != -1:
+        elif isinstance(args[0], wxSizerPtr):
             apply(self.InsertSizer, args, kw)
         else:
             apply(self.InsertWindow, args, kw)
@@ -191,7 +190,7 @@ public:
     def Prepend(self, *args, **kw):
         if type(args[0]) == type(1):
             apply(self.PrependSpacer, args, kw)
-        elif string.find(args[0].this, 'Sizer') != -1:
+        elif isinstance(args[0], wxSizerPtr):
             apply(self.PrependSizer, args, kw)
         else:
             apply(self.PrependWindow, args, kw)
@@ -199,7 +198,7 @@ public:
     def Remove(self, *args, **kw):
         if type(args[0]) == type(1):
             return apply(self.RemovePos, args, kw)
-        elif string.find(args[0].this, 'Sizer') != -1:
+        elif isinstance(args[0], wxSizerPtr):
             return apply(self.RemoveSizer, args, kw)
         else:
             return apply(self.RemoveWindow, args, kw)
@@ -223,7 +222,7 @@ public:
     def SetItemMinSize(self, *args):
         if type(args[0]) == type(1):
             apply(self.SetItemMinSizePos, args)
-        elif string.find(args[0].this, 'Sizer') != -1:
+        elif isinstance(args[0], wxSizerPtr):
             apply(self.SetItemMinSizeSizer, args)
         else:
             apply(self.SetItemMinSizeWindow, args)
@@ -277,19 +276,19 @@ public:
 
     %pragma(python) addtoclass = "
     def Show(self, *args):
-        if string.find(args[0].this, 'Sizer') != -1:
+        if isinstance(args[0], wxSizerPtr):
             apply(self.ShowSizer, args)
         else:
             apply(self.ShowWindow, args)
 
     def Hide(self, *args):
-        if string.find(args[0].this, 'Sizer') != -1:
+        if isinstance(args[0], wxSizerPtr):
             apply(self.HideSizer, args)
         else:
             apply(self.HideWindow, args)
 
     def IsShown(self, *args):
-        if string.find(args[0].this, 'Sizer') != -1:
+        if isinstance(args[0], wxSizerPtr):
             return apply(self.IsShownSizer, args)
         else:
             return apply(self.IsShownWindow, args)
diff --git a/wxPython/src/streams.i b/wxPython/src/streams.i
index a0776cdf64..8bf7f2156d 100644
--- a/wxPython/src/streams.i
+++ b/wxPython/src/streams.i
@@ -28,7 +28,6 @@
 %import _defs.i
 
 %pragma(python) code = "import wx"
-%pragma(python) code = "import string"
 
 //----------------------------------------------------------------------
 // typemaps for wxInputStream
diff --git a/wxPython/src/utils.i b/wxPython/src/utils.i
index 07aa916f60..9b19149c5f 100644
--- a/wxPython/src/utils.i
+++ b/wxPython/src/utils.i
@@ -35,7 +35,7 @@
 // Import some definitions of other classes, etc.
 %import _defs.i
 
-%pragma(python) code = "import string"
+%pragma(python) code = "import wx"
 
 
 //---------------------------------------------------------------------------
@@ -762,17 +762,17 @@ public:
 
     %pragma(python) addtoclass = "
     def __add__(self, other):
-        if string.find(other.this, 'wxTimeSpan') != -1:
+        if isinstance(other, wxTimeSpanPtr):
             return self.__add__TS(other)
-        if string.find(other.this, 'wxDateSpan') != -1:
+        if isinstance(other, wxDateSpanPtr):
             return self.__add__DS(other)
         raise TypeError, 'Invalid r.h.s. type for __add__'
     def __sub__(self, other):
-        if string.find(other.this, 'wxDateTime') != -1:
+        if isinstance(other, wxDateTimePtr):
             return self.__sub__DT(other)
-        if string.find(other.this, 'wxTimeSpan') != -1:
+        if isinstance(other, wxTimeSpanPtr):
             return self.__sub__TS(other)
-        if string.find(other.this, 'wxDateSpan') != -1:
+        if isinstnace(other, wxDateSpanPtr):
             return self.__sub__DS(other)
         raise TypeError, 'Invalid r.h.s. type for __sub__'
 "