Python 2.5 adds a simple way to pass values \emph{into} a generator.
As introduced in Python 2.3, generators only produce output; once a
-generator's code is invoked to create an iterator, there's no way to
+generator's code was invoked to create an iterator, there was no way to
pass any new information into the function when its execution is
resumed. Sometimes the ability to pass in some information would be
useful. Hackish solutions to this include making the generator's code
Generators also become \emph{coroutines}, a more generalized form of
subroutines. Subroutines are entered at one point and exited at
-another point (the top of the function, and a \keyword{return
-statement}), but coroutines can be entered, exited, and resumed at
+another point (the top of the function, and a \keyword{return}
+statement), but coroutines can be entered, exited, and resumed at
many different points (the \keyword{yield} statements). We'll have to
figure out patterns for using coroutines effectively in Python.