PEP8 cleanup

compiler/drc/design_rules.py

@@ -9,6 +9,7 @@ import debug
 from drc_value import *
 from drc_lut import *
 
+
 class design_rules(dict):
     """
     This is a class that implements the design rules structures.

compiler/drc/drc_lut.py

@@ -7,6 +7,7 @@
 #
 import debug
 
+
 class drc_lut():
     """
     Implement a lookup table of rules.
@@ -32,7 +33,6 @@ class drc_lut():
             if self.match(key, table_key):
                 return self.table[table_key]
 
-
     def match(self, key1, key2):
         """
         Determine if key1>=key2 for all tuple pairs.

compiler/drc/drc_value.py

@@ -6,6 +6,7 @@
 # All rights reserved.
 #
 
+
 class drc_value():
     """
     A single DRC value.