error:not a Tk object
 Tk::die_with_trace at G:/Dwimperl/Perl/site/lib/Tk.pm line 251
 Tk::__ANON__ at final_code.pl line 141
 main::push_button1 at G:/Dwimperl/Perl/site/lib/Tk.pm line 251
(eval) at  G:/Dwimperl/Perl/site/lib/Tk.pm  line 251
Tk::__ANON__ at G:/Dwimperl/Perl/site/lib/Tk/Button.pm  line 175
Tk::Button::butUp at  G:/Dwimperl/Perl/site/lib/Tk.pm  line 424
(eval) at  G:/Dwimperl/Perl/site/lib/Tk.pm  line 424
 
 Tk::MainLoop at final_code.pl line 87
Tk callback for .button
Tk::__ANON__ at G:/Dwimperl/Perl/site/lib/Tk.pm line 251
Tk::Button::butUp at  G:/Dwimperl/Perl/site/lib/Tk.pm  line 175
<Button-Release1>