temporal framework: Fixed bug in algebra expression that contains temporal topological statements in the if section

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@66541 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/python/temporal/temporal_raster_base_algebra.py

@@ -1509,10 +1509,10 @@ class TemporalRasterBaseAlgebraParser(TemporalAlgebraParser):
                 theninput = self.check_stds(t[7])
                 elseinput = str(t[9])
         elif len(t) == 13:
-            if isinstance(t[7],  int):
+            if t[7] == 'null':
                 theninput = str(t[7] + t[8] + t[9])
                 elseinput = self.check_stds(t[11])
-            elif isinstance(t[9],  int):
+            elif t[9] == 'null':
                 theninput = self.check_stds(t[7])
                 elseinput = str(t[9] + t[10] + t[11])