diff --git a/IfxAlchemy/IfxPy.py b/IfxAlchemy/IfxPy.py
index 6c0d9ec..f8cc797 100644
--- a/IfxAlchemy/IfxPy.py
+++ b/IfxAlchemy/IfxPy.py
@@ -128,7 +128,7 @@ def do_execute(self, cursor, statement, parameters, context=None):
     _isolation_levels_returned = { value : key for key, value in _isolation_levels_cli.items()}
 
     def _get_cli_isolation_levels(self, level):
-        return _isolation_levels_cli[level]
+        return self._isolation_levels_cli[level]
 
     def set_isolation_level(self, connection, level):
         if level is  None:
@@ -143,7 +143,7 @@ def set_isolation_level(self, connection, level):
                 "Valid isolation levels for %s are %s" %
                 (level, self.name, ", ".join(self._isolation_lookup))
             )
-        attrib = {SQL_ATTR_TXN_ISOLATION:_get_cli_isolation_levels(self,level)}
+        attrib = {SQL_ATTR_TXN_ISOLATION: self._get_cli_isolation_levels(level)}
         res = connection.set_option(attrib)
 
     def reset_isolation_level(self, connection):
diff --git a/IfxAlchemy/base.py b/IfxAlchemy/base.py
index 57f3390..12b3192 100644
--- a/IfxAlchemy/base.py
+++ b/IfxAlchemy/base.py
@@ -400,9 +400,9 @@ def visit_select(self, select, **kwargs):
             sql = '%s, ( ROW_NUMBER() OVER() ) AS "%s" FROM ( %s ) AS M' % ( sql_sel, __rownum, sql_pri )
             sql = '%s FROM ( %s ) Z WHERE' % ( sql_sel, sql )
 
-            if offset is not 0:
+            if offset != 0:
                 sql = '%s "%s" > %d' % ( sql, __rownum, offset )
-            if offset is not 0 and limit is not None:
+            if offset != 0 and limit is not None:
                 sql = '%s AND ' % ( sql )
             if limit is not None:
                 sql = '%s "%s" <= %d' % ( sql, __rownum, offset + limit )