+=item do_edit
+
+If there is an object in C<$r-E<gt>objects>, then it should be edited
+with the parameters in C<$r-E<gt>params>; otherwise, a new object should
+be created with those parameters, and put back into C<$r-E<gt>objects>.
+The template should be changed to C<view>, or C<edit> if there were any
+errors. A hash of errors will be passed to the template.
+
+=cut
+
+sub do_edit { die "This is an abstract method" }
+