typo fix

Author: uvpasapp

creational/borg.py

@@ -24,7 +24,7 @@
 attributes will also be shared.
 For this reason, when the attribute self.state is modified using
 instance rm2, the value of self.state in instance rm1 also chages. The
-same happends if self.state is modified using rm3, which is an
+same happens if self.state is modified using rm3, which is an
 instance from a subclass.
 Notice that even though they share attributes, the instances are not
 the same, as seen by their ids.