Addresses https://github.com/pyeve/cerberus/issues/568.
Backported upstream commit 5c267b554a39b5a8650659d3eea0cf383e47a166.

--- a/cerberus/errors.py
+++ b/cerberus/errors.py
@@ -153,7 +153,7 @@
 
     @property
     def definitions_errors(self):
-        """
+        r"""
         Dictionary with errors of an \*of-rule mapped to the index of the definition it
         occurred in. Returns :obj:`None` if not applicable.
         """
@@ -181,7 +181,7 @@
 
     @property
     def is_logic_error(self):
-        """
+        r"""
         ``True`` for validation errors against different schemas with \*of-rules.
         """
         return bool(self.code & LOGICAL.code - ERROR_GROUP.code)