PEP 8 section on string quotes by Akira Li.

pep-0008.txt

@@ -390,6 +390,19 @@ Imports
   public and internal interfaces still apply.
 
 
+String Quotes
+=============
+
+In Python, single-quoted strings and double-quoted strings are the
+same.  This PEP do not make a recommendation for this.  Pick a rule
+and stick to it.  When a string contains single or double quote
+characters, however, use the other one to avoid backslashes in the
+string.  It improves readability.
+
+For triple-quoted strings, always use double quote characters to be
+consistent with the docstring convention in PEP 257.
+
+
 Whitespace in Expressions and Statements
 ========================================