diff --git a/Doc/library/test.rst b/Doc/library/test.rst
index d196678..2da63ac 100644
--- a/Doc/library/test.rst
+++ b/Doc/library/test.rst
@@ -384,8 +384,13 @@
 .. class:: EnvironmentVarGuard()
 
    Class used to temporarily set or unset environment variables.  Instances can be
-   used as a context manager.
+   used as a context manager and have a complete dictionary interface for
+   querying/modifying the underlying ``os.environ``. After exit from the context
+   manager all changes to environment variables done through this instance will
+   be rolled back.
 
+   .. versionchanged:: 2.7
+      Added dictionary interface.
 
 .. method:: EnvironmentVarGuard.set(envvar, value)
 
@@ -396,6 +401,7 @@
 
    Temporarily unset the environment variable ``envvar``.
 
+
 .. class:: WarningsRecorder()
 
    Class used to record warnings for unit tests. See documentation of