CMake: Fix python warnings

CMake/generate.py

@@ -267,7 +267,7 @@ class Generator:
                 incl += Config.get_array(CONFIG, 'CMake:Deps:{}'.format(dep), 'include', fallback=[])
                 libs += Config.get_array(CONFIG, 'CMake:Deps:{}'.format(dep), 'link', fallback=[])
                 f = Config.get(CONFIG, 'CMake:Deps:{}'.format(dep), 'find', fallback="")
-                if f is not "":
+                if f != "":
                     find.append(f)
             except ConfigException:
                 print("Warning: System dependency '{}' is not configured".format(dep), file=sys.stderr)
@@ -315,7 +315,7 @@ def compute_packages(packages, groups, no_dependencies, no_test_dependencies, ve
     res = set()
     # no packages specified, i.e. return all
-    if len(packages) is 0:
+    if len(packages) == 0:
         packages = PROJECTS.values()
     # possibly compute dependencies