diff --git a/anuga/damage_modelling/exposure.py b/anuga/damage_modelling/exposure.py
index 282d51549..ef4fb1db0 100644
--- a/anuga/damage_modelling/exposure.py
+++ b/anuga/damage_modelling/exposure.py
@@ -1,4 +1,4 @@
-from past.builtins import cmp
+
 from builtins import zip
 from builtins import range
 from builtins import object
@@ -17,7 +17,8 @@
 X_TITLE = 'x'
 Y_TITLE = 'y'
 
-
+def cmp_0(a, b):
+    return (a > b) - (a < b)
 
 class Exposure(object):
     """Class for National Exposure Database storage (NEXIS).
@@ -110,17 +111,17 @@ def __cmp__(self, other):
 
         #check that 'other' is an instance of this class
         if isinstance(self, type(other)):
-            result = cmp(self._attribute_dic, other._attribute_dic)
+            result = cmp_0(self._attribute_dic, other._attribute_dic)
             if result != 0:
                 return result
 
             # The order of the columns is important. Therefore..
-            result = cmp(self._title_index_dic, other._title_index_dic)
+            result = cmp_0(self._title_index_dic, other._title_index_dic)
             if result != 0:
                 return result
             for self_ls, other_ls in zip(self._attribute_dic,
                                          other._attribute_dic):
-                result = cmp(self._attribute_dic[self_ls],
+                result = cmp_0(self._attribute_dic[self_ls],
                              other._attribute_dic[other_ls])
                 if result != 0:
                     return result
@@ -161,12 +162,12 @@ def __eq__(self, other):
             #    return result
 
             # The order of the columns is important. Therefore..
-            #result = cmp(self._title_index_dic, other._title_index_dic)
+            #result = cmp_0(self._title_index_dic, other._title_index_dic)
             #if result != 0:
             #    return result
             #for self_ls, other_ls in zip(self._attribute_dic,
             #                             other._attribute_dic):
-            #    result = cmp(self._attribute_dic[self_ls],
+            #    result = cmp_0(self._attribute_dic[self_ls],
             #                 other._attribute_dic[other_ls])
             #    if result != 0:
             #        return result
diff --git a/anuga/utilities/model_tools.py b/anuga/utilities/model_tools.py
index 242a67ede..c3a504159 100644
--- a/anuga/utilities/model_tools.py
+++ b/anuga/utilities/model_tools.py
@@ -76,7 +76,7 @@
 from anuga.utilities.model_tools import get_BUILDING_polygon_value_list
 """
 
-from past.builtins import execfile
+
 import os
 import glob
 import numpy
@@ -434,7 +434,7 @@ def Create_culvert_bridge_Operator(domain,culvert_bridge_file):
     globals={}
     locals={}    
     
-    execfile(culvert_bridge_file, globals, locals)
+    exec(open(culvert_bridge_file).read(), globals, locals) 
     #print locals
     #if 'height' and 'z1' and 'z2' in locals:
     if 'z1' and 'z2' in locals:
diff --git a/run_validations.py b/run_validations.py
index 10eb13746..dc6a85012 100644
--- a/run_validations.py
+++ b/run_validations.py
@@ -1,5 +1,4 @@
-from __future__ import print_function
-from past.builtins import execfile
+
 import os
 
 
@@ -7,5 +6,5 @@
 print()
 print(20*'=' + ' anuga automated validation tests ' + 20*'=')
 print('Changing to', os.getcwd()) # This is now different from buildroot   
-execfile('run_auto_validation_tests.py')
+exec(open('run_auto_validation_tests.py').read())