\class{FancyURLopener} class and use it to perform their requested
actions. To override this functionality, programmers can create a
subclass of \class{URLopener} or \class{FancyURLopener}, then assign
-that an instance of that class to the
+an instance of that class to the
\code{urllib._urlopener} variable before calling the desired function.
For example, applications may want to specify a different
\mailheader{User-Agent} header than \class{URLopener} defines. This