use v5.14;
use warnings;
use DBI ();

package MyApp {
   
   sub do_something {
      my ($version, $dbh, $output_file) = @_;
      if ( $version < 1.0 ) {  # a local variable
         do_something_simple($output_file);
      }
      else {
         do_something_complex($output_file, $dbh);
      }
   }
   
   sub do_something_simple {
      my ($output_file) = @_;
      open my $fh, '>', $output_file or die;
      print $fh "Hello world\n";
   }
   
   sub do_something_complex {
      my ($output_file, $dbh) = @_;
      open my $fh, '>', $output_file or die;
      print $fh "Hello world\n";
      printf $fh "There are %d rows in the table.\n",
         $dbh->do("SELECT 1 FROM my_table");
   }
}

MyApp::do_something(
   1.2,
   DBI->connect("dbi:SQLite:dbname=myapp.sqlite"),
   '/tmp/output.txt',
);