Index: src/sas/sascalc/realspace/VolumeCanvas.py
===================================================================
--- src/sas/sascalc/realspace/VolumeCanvas.py	(revision d85c194ea2f78cb2b9b3de9c969e1b8ebea6b6d2)
+++ src/sas/sascalc/realspace/VolumeCanvas.py	(revision f3bf622b821c651bb6e946100b07e15cd59331fe)
@@ -303,5 +303,5 @@
         self.shapecount += 1
 
-        #model changed, need to recalculate P(r)
+        # model changed, need to recalculate P(r)
         self._model_changed()
 
@@ -328,5 +328,5 @@
             id = "shape"+str(self.shapecount)
  
-        #shapeDesc = ShapeDescriptor(shape.lower())
+        # shapeDesc = ShapeDescriptor(shape.lower())
         if shape.lower() in shape_dict:
             shapeDesc = shape_dict[shape.lower()]()
@@ -335,5 +335,5 @@
             shapeDesc = PDBDescriptor(shape)
         else:
-            raise ValueError, "VolumeCanvas.add: Unknown shape %s" % shape
+            raise ValueError("VolumeCanvas.add: Unknown shape %s" % shape)
         
         return self.addObject(shapeDesc, id)
@@ -345,10 +345,10 @@
         """
 
-        if self.shapes.has_key(id):
+        if id in self.shapes:
             del self.shapes[id]
         else:
-            raise KeyError, "VolumeCanvas.delete: could not find shape ID"
-
-        #model changed, need to recalculate P(r)
+            raise KeyError("VolumeCanvas.delete: could not find shape ID")
+
+        # model changed, need to recalculate P(r)
         self._model_changed()
 
@@ -410,13 +410,13 @@
         if len(toks) == 1:
             try:
-                self.params.has_key(toks[0])
+                a = self.params[toks[0]]
             except KeyError:
-                raise ValueError, \
-                    "VolumeCanvas.getParam: Could not find %s" % name
+                raise ValueError("VolumeCanvas.getParam: Could not find"
+                                 " %s" % name)
 
             value = self.params[toks[0]]
             if isinstance(value, ShapeDescriptor):
-                raise ValueError, \
-                    "VolumeCanvas.getParam: Cannot get parameter value." 
+                raise ValueError("VolumeCanvas.getParam: Cannot get parameter"
+                                 " value.")
             else:
                 return value
@@ -424,22 +424,21 @@
         elif len(toks) == 2:
             try:
-                self.shapes.has_key(toks[0])
+                a = self.shapes[toks[0]]
             except KeyError:
-                raise ValueError, \
-                    "VolumeCanvas.getParam: Could not find %s" % name
+                raise ValueError("VolumeCanvas.getParam: Could not find "
+                                 "%s" % name)
 
             shapeinstance = self.shapes[toks[0]]
 
             try:
-                shapeinstance.params.has_key(toks[1])
+                a = shapeinstance.params[toks[1]]
             except KeyError:
-                raise ValueError, \
-                    "VolumeCanvas.getParam: Could not find %s" % name
+                raise ValueError("VolumeCanvas.getParam: Could not find "
+                                 "%s" % name)
 
             return shapeinstance.params[toks[1]]
 
         else:
-            raise ValueError, \
-                "VolumeCanvas.getParam: Could not find %s" % name
+            raise ValueError("VolumeCanvas.getParam: Could not find %s" % name)
             
     def getParamList(self, shapeid = None):
@@ -455,5 +454,5 @@
 
         param_list = []
-        if shapeid == None:        
+        if shapeid is None:
             for key1 in self.params.keys():
                 #value1 = self.params[key1]
@@ -468,13 +467,11 @@
         else:
             try:
-                self.shapes.has_key(shapeid)
+                a = self.shapes[shapeid]
             except KeyError:
-                raise ValueError, \
-                    "VolumeCanvas: getParamList: Could not find %s" % shapeid
+                raise ValueError("VolumeCanvas: getParamList: Could not find "
+                                 "%s" % shapeid)
+
             header = shapeid + '.'
-            param_list = self.shapes[shapeid].params.keys()  
-            for i in range(len(param_list)):
-                param_list[i] = header + param_list[i]
-
+            param_list = [header + param for param in self.shapes[shapeid].params]
         return param_list
 
