<p>
If <code>doParse</code> panics, the recovery block will set the
return value to <code>nil</code>—deferred functions can modify
-named return values. It then will then check, in the assignment
+named return values. It will then check, in the assignment
to <code>err</code>, that the problem was a parse error by asserting
that it has the local type <code>Error</code>.
If it does not, the type assertion will fail, causing a run-time error