$ perl -e 'use Tk; MainWindow->new()->Button(-text => "?")->pack(-pady => 2); MainLoop'

##</code><code>##

$ perl -e 'use Tk; MainWindow->new()->Button(-text => "?")->pack(pady => 2); MainLoop'
bad option "pady": must be -after, -anchor, -before, -expand, -fill, -in, -ipadx, -ipady, -padx, -pady, or -side at /long/path/to/Tk/Widget.pm line 1217.
 at -e line 1.

##</code><code>##

$ perl -e 'use Tk; MainWindow->new()->Button(text => "?")->pack(-pady => 2); MainLoop'
unknown option "text" at /long/path/to/Tk/Widget.pm line 205.
 at -e line 1.