Update configparser.py

Author: lpyu001

Lib/configparser.py

@@ -1223,7 +1223,9 @@ def _convert_to_boolean(self, value):
         """Return a boolean value translating from other types if necessary.
         """
         if value is None:
-            raise TypeError('Cannot convert a value-less option to a boolean')
+            raise TypeError(
+                "getboolean() option value must be a string, not 'NoneType'"
+            )
         if value.lower() not in self.BOOLEAN_STATES:
             raise ValueError('Not a boolean: %s' % value)
         return self.BOOLEAN_STATES[value.lower()]