Cleanup pylint errors

tools/pretty_sln.py

Index: tools/pretty_sln.py
diff --git a/tools/pretty_sln.py b/tools/pretty_sln.py
index 3195d8581bebee270fc8e2bfc07a899b78e1fc70..ca8cf4ad3fb836bd39f40e368dda79735c585a6a 100755
--- a/tools/pretty_sln.py
+++ b/tools/pretty_sln.py
@@ -38,12 +38,13 @@ def ParseSolution(solution_file):
 
   # Regular expressions that matches the SLN format.
   # The first line of a project definition.
-  begin_project = re.compile(('^Project\("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942'
-                              '}"\) = "(.*)", "(.*)", "(.*)"$'))
+  begin_project = re.compile(r'^Project\("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942'
+                             r'}"\) = "(.*)", "(.*)", "(.*)"$')
   # The last line of a project definition.
   end_project = re.compile('^EndProject$')
   # The first line of a dependency list.
-  begin_dep = re.compile('ProjectSection\(ProjectDependencies\) = postProject$')
+  begin_dep = re.compile(
+      r'ProjectSection\(ProjectDependencies\) = postProject$')
   # The last line of a dependency list.
   end_dep = re.compile('EndProjectSection$')
   # A line describing a dependency.