In the following code, it is the version number is defined
by the constant
and all package variables of the form our $package::VERSION
refer to the constant function which is inherited by default.
In this way, all normal queries for version information get the same
number from the same source. Is this what you wanted?
use constant VERSION => '5.0';
use base 'Person';
print 'version=', $Person::VERSION;
print 'version=', $American::VERSION;