cosmetic: whitespace in log.py

Change-Id: I356725ba7d874d3d41afb5e4c89dac188c8d7dcc
diff --git a/src/osmo_gsm_tester/log.py b/src/osmo_gsm_tester/log.py
index d662400..ede3b16 100644
--- a/src/osmo_gsm_tester/log.py
+++ b/src/osmo_gsm_tester/log.py
@@ -445,8 +445,6 @@
     exception.origins.add(origin)
     return False
 
-
-
 def log_exn(origin=None, category=None, exc_info=None):
     if not (exc_info is not None and len(exc_info) == 3):
         exc_info = sys.exc_info()
@@ -482,6 +480,7 @@
     def __init__(self, origin=None):
         if origin is not None:
             self.add(origin)
+
     def add(self, origin):
         if hasattr(origin, 'name'):
             origin_str = origin.name()
@@ -490,11 +489,11 @@
         if origin_str is None:
             raise RuntimeError('origin_str is None for %r' % origin)
         self.insert(0, origin_str)
+
     def __str__(self):
         return '↪'.join(self)
 
 
-
 def set_all_levels(level):
     for target in LogTarget.all_targets:
         target.set_all_levels(level)