diff --git a/python/plugins/processing/core/AlgorithmProvider.py b/python/plugins/processing/core/AlgorithmProvider.py
index 4997cdc63a1..6a51fbd4a18 100644
--- a/python/plugins/processing/core/AlgorithmProvider.py
+++ b/python/plugins/processing/core/AlgorithmProvider.py
@@ -31,7 +31,7 @@ from qgis.core import QgsVectorFileWriter
 from processing.core.ProcessingConfig import Setting, ProcessingConfig
 
 
-class AlgorithmProvider:
+class AlgorithmProvider(object):
     """This is the base class for algorithms providers.
 
     An algorithm provider is a set of related algorithms, typically
diff --git a/python/plugins/processing/core/GeoAlgorithm.py b/python/plugins/processing/core/GeoAlgorithm.py
index ead63bbab44..3f3d57082c7 100644
--- a/python/plugins/processing/core/GeoAlgorithm.py
+++ b/python/plugins/processing/core/GeoAlgorithm.py
@@ -142,7 +142,7 @@ class GeoAlgorithm:
         return False, helpUrl
 
 
-    def processAlgorithm(self):
+    def processAlgorithm(self, progress):
         """Here goes the algorithm itself.
 
         There is no return value from this method.
@@ -229,10 +229,10 @@ class GeoAlgorithm:
             progress.setPercentage(100)
             self.convertUnsupportedFormats(progress)
             self.runPostExecutionScript(progress)
-        except GeoAlgorithmExecutionException, gaee:
+        except GeoAlgorithmExecutionException as gaee:
             ProcessingLog.addToLog(ProcessingLog.LOG_ERROR, gaee.msg)
             raise gaee
-        except Exception, e:
+        except Exception as e:
             # If something goes wrong and is not caught in the
             # algorithm, we catch it here and wrap it
             lines = [self.tr('Uncaught error while executing algorithm')]
diff --git a/python/plugins/processing/gui/AlgorithmExecutor.py b/python/plugins/processing/gui/AlgorithmExecutor.py
index acd38b4b6f0..19e417ec24e 100644
--- a/python/plugins/processing/gui/AlgorithmExecutor.py
+++ b/python/plugins/processing/gui/AlgorithmExecutor.py
@@ -50,7 +50,7 @@ def runalg(alg, progress=None):
     try:
         alg.execute(progress)
         return True
-    except GeoAlgorithmExecutionException, e:
+    except GeoAlgorithmExecutionException as e:
         ProcessingLog.addToLog(sys.exc_info()[0], ProcessingLog.LOG_ERROR)
         progress.error(e.msg)
         return False
diff --git a/python/plugins/processing/gui/SilentProgress.py b/python/plugins/processing/gui/SilentProgress.py
index 5b89a812032..cff916fd240 100644
--- a/python/plugins/processing/gui/SilentProgress.py
+++ b/python/plugins/processing/gui/SilentProgress.py
@@ -26,7 +26,7 @@ __copyright__ = '(C) 2013, Victor Olaya'
 __revision__ = '$Format:%H$'
 
 
-class SilentProgress:
+class SilentProgress(object):
 
     def error(self, msg):
         print msg