Converting YES/NO to true/false

[ivanacostarubio]

I hope this help! :-)

[kyamaguchi]

Thanks a lot.
I will merge this.

And also I will change expression a little later.

     def convert_boolean(self):
-        self.s = re.sub('YES','true', self.s)
-        self.s = re.sub('NO','false', self.s)
+        self.s = re.sub(r'\bYES\b','true', self.s)
+        self.s = re.sub(r'\bNO\b','false', self.s)
         return self

This will avoid unexpected replacement of YES/NO in words like 'ZNOAuth' or something else.