diff --git a/plugins/disk/btrfs_device_stats b/plugins/disk/btrfs_device_stats
index 53bd359e..de82dc82 100755
--- a/plugins/disk/btrfs_device_stats
+++ b/plugins/disk/btrfs_device_stats
@@ -90,8 +90,8 @@ def munin_config(fs):
     print("")
 
     devices = fs.devices()
-    warning = os.getenv('warning', default = 1)
-    critical = os.getenv('critical', default = False)
+    warning = os.getenv('warning', default=1)
+    critical = os.getenv('critical', default=False)
     for this_device in devices:
         this_dev_info = fs.dev_info(this_device.devid)
         this_dev_name = this_dev_info.path.replace('/dev/', '')
@@ -105,49 +105,49 @@ def munin_config(fs):
 
         print("corruption_errs.label Corruption Errors")
         print("corruption_errs.warning " + os.getenv('corruption_errs_warning',
-              default = str(warning)))
-        if os.getenv('corruption_errs_critical', default = critical):
+              default=str(warning)))
+        if os.getenv('corruption_errs_critical', default=critical):
             print("corruption_errs.critical " +
                   os.getenv('corruption_errs_critical',
-                  default = str(critical)))
+                  default=str(critical)))
 
         print("flush_errs.label Flush Errors")
         print("flush_errs.warning " + os.getenv('flush_errs_warning',
               default = str(warning)))
-        if os.getenv('flush_errs_critical', default = critical):
+        if os.getenv('flush_errs_critical', default=critical):
             print("flush_errs.critical " + os.getenv('flush_errs_critical',
-                  default = str(critical)))
+                  default=str(critical)))
 
         print("generation_errs.label Generation Errors")
         print("generation_errs.warning " + os.getenv('generation_errs_warning',
-              default = str(warning)))
-        if os.getenv('generation_errs_critical', default = critical):
+              default=str(warning)))
+        if os.getenv('generation_errs_critical', default=critical):
             print("generation_errs.critical " +
                   os.getenv('generation_errs_critical',
-                  default = str(critical)))
+                  default=str(critical)))
 
         print("read_errs.label Read Errors")
         print("read_errs.warning " + os.getenv('read_errs_warning',
-              default = str(warning)))
-        if os.getenv('read_errs_critical', default = critical):
+              default=str(warning)))
+        if os.getenv('read_errs_critical', default=critical):
             print("read_errs.critical " + os.getenv('read_errs_critical',
-                  default = str(critical)))
+                  default=str(critical)))
 
         print("write_errs.label Write Errors")
         print("write_errs.warning " + os.getenv('write_errs_warning',
-              default = str(warning)))
-        if os.getenv('write_errs_critical', default = critical):
+              default=str(warning)))
+        if os.getenv('write_errs_critical', default=critical):
             print("write_errs.critical " + os.getenv('write_errs_critical',
-                  default = str(critical)))
+                  default=str(critical)))
 
         print("nr_items.label Nr. of Items")
 
         print("flags.label Nr. of Flags")
         print("flags.warning " + os.getenv('flags_warning',
-              default = str(warning)))
-        if os.getenv('flags_critical', default = critical):
+              default=str(warning)))
+        if os.getenv('flags_critical', default=critical):
             print("flags.critical " + os.getenv('flags_critical',
-                  default = str(critical)))
+                  default=str(critical)))
 
         print("")
 
diff --git a/plugins/disk/btrfs_device_usage b/plugins/disk/btrfs_device_usage
index 09124013..519e10d5 100755
--- a/plugins/disk/btrfs_device_usage
+++ b/plugins/disk/btrfs_device_usage
@@ -75,19 +75,19 @@ import sys
 def munin_config(fs):
     fsid = str(fs.fsid).replace('-', '_')
 
-    byte_warning = os.getenv('byte_warning', default = False)
-    byte_critical = os.getenv('byte_critical', default = False)
+    byte_warning = os.getenv('byte_warning', default=False)
+    byte_critical = os.getenv('byte_critical', default=False)
     byte_warning = os.getenv('byte_' + fsid + '_warning',
-                             default = byte_warning)
+                             default=byte_warning)
     byte_critical = os.getenv('byte_' + fsid + '_critical',
-                              default = byte_critical)
+                              default=byte_critical)
 
-    percent_warning = os.getenv('percent_warning', default = 95)
-    percent_critical = os.getenv('percent_critical', default = 98)
+    percent_warning = os.getenv('percent_warning', default=95)
+    percent_critical = os.getenv('percent_critical', default=98)
     percent_warning = os.getenv('percent_' + fsid + '_warning',
-                                default = percent_warning)
+                                default=percent_warning)
     percent_critical = os.getenv('percent_' + fsid + '_critical',
-                                 default = percent_critical)
+                                 default=percent_critical)
 
     print("multigraph btrfs_device_usage_byte_" + fsid)
     print("graph_title btrfs usage by device in bytes on " + fs.path)