diff --git a/platron/sig_helper.py b/platron/sig_helper.py
index 46b9fc9..d9f0427 100644
--- a/platron/sig_helper.py
+++ b/platron/sig_helper.py
@@ -26,14 +26,14 @@ def __make_flat_params_xml(self, xml_str, parent_name=''):
                 continue
 
             name = parent_name + child.tag + "{:03d}".format(i)
-            if self.flat_xml_array.get(name) != None:
+            if self.flat_xml_array.get(name) is not None:
                 name = name + '_doubled'
 
-            if child.getchildren() != []:
+            if list(child):
                 self.__make_flat_params_xml(child, name)
                 continue
 
-            if child.text == None:
+            if child.text is None:
                 self.flat_xml_array.update({name: ''})
             else:
                 self.flat_xml_array.update({name: child.text})
diff --git a/tox.ini b/tox.ini
index 944b9f5..8a0839e 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py27,py33,py34,py35,py36
+envlist = py27,py33,py34,py35,py36,py38
 toxworkdir=../tox
 
 [testenv]