Update README.md

Author: jph00

README.md

@@ -20,7 +20,7 @@ Note that this requires python 3.6 or later.
 
 ## Usage
 
-Here is a simple example. Each bar takes a generator as a main argument, and we can specify the second bar is nested with the first by adding the argument parent=mb. We can then
+Here is a simple example. Each bar takes an iterator as a main argument, and we can specify the second bar is nested with the first by adding the argument parent=mb. We can then
 - add a comment in the first bar by changing the value of mb.first_bar.comment
 - add a comment in the first bar by changing the value of mb.child.comment
 - write a line between the two bars with mb.write('message')