stderr is always string, so we can remove None check

Author: ArneTR

metric_providers/powermetrics/provider.py

@@ -181,7 +181,7 @@ def read_metrics(self, run_id, containers=None):
     def get_stderr(self):
         stderr = super().get_stderr()
 
-        if stderr is not None and stderr.find('proc_pid') != -1:
+        if stderr.find('proc_pid') != -1:
             return None
 
         return stderr

runner.py

@@ -962,7 +962,7 @@ def start_metric_providers(self, allow_container=True, allow_other=True):
 
             stderr_read = metric_provider.get_stderr()
             print(f"Stderr check on {metric_provider.__class__.__name__}")
-            if stderr_read is not None and stderr_read != '':
+            if stderr_read:
                 raise RuntimeError(f"Stderr on {metric_provider.__class__.__name__} was NOT empty: {stderr_read}")
 
 
@@ -1096,7 +1096,7 @@ def stop_metric_providers(self):
                 continue
 
             stderr_read = metric_provider.get_stderr()
-            if stderr_read is not None and stderr_read != '':
+            if stderr_read:
                 errors.append(f"Stderr on {metric_provider.__class__.__name__} was NOT empty: {stderr_read}")
 
             metric_provider.stop_profiling()