Hello , I'm moving my scripts to packages, but there is an error I can't understand why it happens.
For example Gl/Df.pm:

package Gl::Df;

use strict;
use warnings;
require Exporter;

our @ISA = qw(Exporter);
our @EXPORT = qw( tst1 );
our $VERSION = 1.00;

use Gl::Uf;
sub tst1 { tst2(); print 1 ;}
1;
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Gl/Uf.pm:

package Gl::Uf;


use strict;
use warnings;
require Exporter;

our @ISA = qw(Exporter);
our @EXPORT = qw( tst2 );
our $VERSION = 1.00;


use Gl::Df;
sub tst2 { tst1();print 2 }

1;
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Writing a script that wants to use both modules and their functions test.pl

use strict;
use warnings;

use Gl::Df;
use Gl::Uf;

tst1();
tst2();
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Error received :

Undefined subroutine &Gl::Uf::tst1 called at Gl/Uf.pm line 14.
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What may be the problem ? tst1 should be exporter to 3 scopes, and it is when I checking in the %Gl::Df:: and %Gl::Uf:: but Perl can't use them
How I can fix that ?
Thanks a lot !