Index: src/sas/sascalc/dataloader/data_info.py
===================================================================
--- src/sas/sascalc/dataloader/data_info.py	(revision 959eb0181ad06828a748f04512f953aad5b31659)
+++ src/sas/sascalc/dataloader/data_info.py	(revision 235f514ba93b57fa63e44309f182acef0b98bb55)
@@ -806,10 +806,10 @@
             # create zero vector
             dy_other = other.dy
-            if other.dy == None or (len(other.dy) != len(other.y)):
+            if other.dy is None or (len(other.dy) != len(other.y)):
                 dy_other = np.zeros(len(other.y))
 
         # Check that we have errors, otherwise create zero vector
         dy = self.dy
-        if self.dy == None or (len(self.dy) != len(self.y)):
+        if self.dy is None or (len(self.dy) != len(self.y)):
             dy = np.zeros(len(self.y))
 
@@ -822,9 +822,9 @@
         dy, dy_other = self._validity_check(other)
         result = self.clone_without_data(len(self.x))
-        if self.dxw == None:
+        if self.dxw is None:
             result.dxw = None
         else:
             result.dxw = np.zeros(len(self.x))
-        if self.dxl == None:
+        if self.dxl is None:
             result.dxl = None
         else:
@@ -884,17 +884,17 @@
         self._validity_check_union(other)
         result = self.clone_without_data(len(self.x) + len(other.x))
-        if self.dy == None or other.dy is None:
+        if self.dy is None or other.dy is None:
             result.dy = None
         else:
             result.dy = np.zeros(len(self.x) + len(other.x))
-        if self.dx == None or other.dx is None:
+        if self.dx is None or other.dx is None:
             result.dx = None
         else:
             result.dx = np.zeros(len(self.x) + len(other.x))
-        if self.dxw == None or other.dxw is None:
+        if self.dxw is None or other.dxw is None:
             result.dxw = None
         else:
             result.dxw = np.zeros(len(self.x) + len(other.x))
-        if self.dxl == None or other.dxl is None:
+        if self.dxl is None or other.dxl is None:
             result.dxl = None
         else:
@@ -1030,5 +1030,5 @@
             # Check that the scales match
             err_other = other.err_data
-            if other.err_data == None or \
+            if other.err_data is None or \
                 (len(other.err_data) != len(other.data)):
                 err_other = np.zeros(len(other.data))
@@ -1036,5 +1036,5 @@
         # Check that we have errors, otherwise create zero vector
         err = self.err_data
-        if self.err_data == None or \
+        if self.err_data is None or \
             (len(self.err_data) != len(self.data)):
             err = np.zeros(len(other.data))
@@ -1051,5 +1051,5 @@
         dy, dy_other = self._validity_check(other)
         result = self.clone_without_data(np.size(self.data))
-        if self.dqx_data == None or self.dqy_data == None:
+        if self.dqx_data is None or self.dqy_data is None:
             result.dqx_data = None
             result.dqy_data = None
@@ -1125,6 +1125,6 @@
         result.ymin = self.ymin
         result.ymax = self.ymax
-        if self.dqx_data == None or self.dqy_data == None or \
-                other.dqx_data == None or other.dqy_data == None:
+        if self.dqx_data is None or self.dqy_data is None or \
+                other.dqx_data is None or other.dqy_data is None:
             result.dqx_data = None
             result.dqy_data = None
Index: src/sas/sascalc/dataloader/manipulations.py
===================================================================
--- src/sas/sascalc/dataloader/manipulations.py	(revision 959eb0181ad06828a748f04512f953aad5b31659)
+++ src/sas/sascalc/dataloader/manipulations.py	(revision 235f514ba93b57fa63e44309f182acef0b98bb55)
@@ -210,5 +210,5 @@
             y[i_q] += frac * data[npts]
 
-            if err_data == None or err_data[npts] == 0.0:
+            if err_data is None or err_data[npts] == 0.0:
                 if data[npts] < 0:
                     data[npts] = -data[npts]
@@ -333,5 +333,5 @@
                 continue
             y += frac * data[npts]
-            if err_data == None or err_data[npts] == 0.0:
+            if err_data is None or err_data[npts] == 0.0:
                 if data[npts] < 0:
                     data[npts] = -data[npts]
@@ -462,5 +462,5 @@
 
         #q_data_max = numpy.max(q_data)
-        if len(data2D.q_data) == None:
+        if len(data2D.q_data) is None:
             msg = "Circular averaging: invalid q_data: %g" % data2D.q_data
             raise RuntimeError, msg
@@ -502,5 +502,5 @@
             # Take dqs from data to get the q_average
             x[i_q] += frac * q_value
-            if err_data == None or err_data[npt] == 0.0:
+            if err_data is None or err_data[npt] == 0.0:
                 if data_n < 0:
                     data_n = -data_n
@@ -623,5 +623,5 @@
             phi_bins[i_phi] += frac * data[npt]
 
-            if err_data == None or err_data[npt] == 0.0:
+            if err_data is None or err_data[npt] == 0.0:
                 if data_n < 0:
                     data_n = -data_n
@@ -888,5 +888,5 @@
             y[i_bin] += frac * data_n
             x[i_bin] += frac * q_value
-            if err_data[n] == None or err_data[n] == 0.0:
+            if err_data[n] is None or err_data[n] == 0.0:
                 if data_n < 0:
                     data_n = -data_n
Index: src/sas/sascalc/dataloader/readers/ascii_reader.py
===================================================================
--- src/sas/sascalc/dataloader/readers/ascii_reader.py	(revision 959eb0181ad06828a748f04512f953aad5b31659)
+++ src/sas/sascalc/dataloader/readers/ascii_reader.py	(revision 235f514ba93b57fa63e44309f182acef0b98bb55)
@@ -128,10 +128,10 @@
                         if new_lentoks > 2:
                             _dy = float(toks[2])
-                        has_error_dy = False if _dy == None else True
+                        has_error_dy = False if _dy is None else True
 
                         # If a 4th row is present, consider it dx
                         if new_lentoks > 3:
                             _dx = float(toks[3])
-                        has_error_dx = False if _dx == None else True
+                        has_error_dx = False if _dx is None else True
 
                         # Delete the previously stored lines of data candidates if
Index: src/sas/sascalc/dataloader/readers/cansas_reader.py
===================================================================
--- src/sas/sascalc/dataloader/readers/cansas_reader.py	(revision 63d773c420797b9a40dbfc28b1e602df82410cae)
+++ src/sas/sascalc/dataloader/readers/cansas_reader.py	(revision 235f514ba93b57fa63e44309f182acef0b98bb55)
@@ -807,5 +807,5 @@
         :param data1d: presumably a Data1D object
         """
-        if self.current_dataset == None:
+        if self.current_dataset is None:
             x_vals = np.empty(0)
             y_vals = np.empty(0)
@@ -895,5 +895,5 @@
         # Write the file
         file_ref = open(filename, 'w')
-        if self.encoding == None:
+        if self.encoding is None:
             self.encoding = "UTF-8"
         doc.write(file_ref, encoding=self.encoding,
@@ -1015,5 +1015,5 @@
         :param entry_node: lxml node ElementTree object to be appended to
         """
-        if datainfo.run == None or datainfo.run == []:
+        if datainfo.run is None or datainfo.run == []:
             datainfo.run.append(RUN_NAME_DEFAULT)
             datainfo.run_name[RUN_NAME_DEFAULT] = RUN_NAME_DEFAULT
@@ -1213,5 +1213,5 @@
                                  str(datainfo.source.name))
         self.append(source, instr)
-        if datainfo.source.radiation == None or datainfo.source.radiation == '':
+        if datainfo.source.radiation is None or datainfo.source.radiation == '':
             datainfo.source.radiation = "neutron"
         self.write_node(source, "radiation", datainfo.source.radiation)
@@ -1254,5 +1254,5 @@
         :param instr: lxml node ElementTree object to be appended to
         """
-        if datainfo.collimation == [] or datainfo.collimation == None:
+        if datainfo.collimation == [] or datainfo.collimation is None:
             coll = Collimation()
             datainfo.collimation.append(coll)
@@ -1299,5 +1299,5 @@
         :param inst: lxml instrument node to be appended to
         """
-        if datainfo.detector == None or datainfo.detector == []:
+        if datainfo.detector is None or datainfo.detector == []:
             det = Detector()
             det.name = ""
Index: src/sas/sascalc/dataloader/readers/danse_reader.py
===================================================================
--- src/sas/sascalc/dataloader/readers/danse_reader.py	(revision 959eb0181ad06828a748f04512f953aad5b31659)
+++ src/sas/sascalc/dataloader/readers/danse_reader.py	(revision 235f514ba93b57fa63e44309f182acef0b98bb55)
@@ -166,7 +166,7 @@
                 
                 x_vals.append(qx)
-                if xmin == None or qx < xmin:
+                if xmin is None or qx < xmin:
                     xmin = qx
-                if xmax == None or qx > xmax:
+                if xmax is None or qx > xmax:
                     xmax = qx
             
@@ -181,7 +181,7 @@
                 
                 y_vals.append(qy)
-                if ymin == None or qy < ymin:
+                if ymin is None or qy < ymin:
                     ymin = qy
-                if ymax == None or qy > ymax:
+                if ymax is None or qy > ymax:
                     ymax = qy
             
Index: src/sas/sascalc/dataloader/readers/xml_reader.py
===================================================================
--- src/sas/sascalc/dataloader/readers/xml_reader.py	(revision 463e7ffce130ae386f93cd18b87a1120743e88b5)
+++ src/sas/sascalc/dataloader/readers/xml_reader.py	(revision 235f514ba93b57fa63e44309f182acef0b98bb55)
@@ -240,5 +240,5 @@
         :param name: The name of the element to be created
         """
-        if attrib == None:
+        if attrib is None:
             attrib = {}
         return etree.Element(name, attrib, nsmap)
@@ -299,5 +299,5 @@
         """
         text = str(text)
-        if attrib == None:
+        if attrib is None:
             attrib = {}
         elem = E(elementname, attrib, text)
