power_Idle: Fix indent for cleanup() & pylint

CL:1185228 mess up cleanup() indent. Fix it.

Also fix pylint errors.

BUG=None
TEST=Ran power_Idle

Change-Id: Ieafd0819900dd7c3064cd5ac9e614aa6c75993af
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/2013552
Tested-by: Puthikorn Voravootivat <puthik@chromium.org>
Commit-Queue: Puthikorn Voravootivat <puthik@chromium.org>
Auto-Submit: Puthikorn Voravootivat <puthik@chromium.org>
Reviewed-by: Todd Broch <tbroch@chromium.org>
diff --git a/client/site_tests/power_Idle/power_Idle.py b/client/site_tests/power_Idle/power_Idle.py
index f8cf5f8..1146e9a 100755
--- a/client/site_tests/power_Idle/power_Idle.py
+++ b/client/site_tests/power_Idle/power_Idle.py
@@ -40,6 +40,7 @@
         """Collect power stats for idle tests."""
 
         def measure_it(warmup_secs, idle_secs, tagname):
+            """Helper function to wrap testing loop for each sub test."""
             if warmup_secs > 0:
                 tstart = time.time()
                 time.sleep(warmup_secs)
@@ -83,6 +84,7 @@
             power_utils.set_display_power(power_utils.DISPLAY_POWER_ALL_OFF)
             measure_it(warmup_secs, idle_secs, 'display-off_bluetooth-on')
 
-def cleanup(self):
-    power_utils.set_display_power(power_utils.DISPLAY_POWER_ALL_ON)
-    super(power_Idle, self).cleanup()
+    def cleanup(self):
+        """Reset to previous state."""
+        power_utils.set_display_power(power_utils.DISPLAY_POWER_ALL_ON)
+        super(power_Idle, self).cleanup()