The set_db method comes from Class:DBI. In theory the MsfdbMaypole::People class should have been set up properly by Class::DBI::Loader, but that does not seem to be the case, as it doesn't seem to have properly inherited from Class::DBI...

Does Class::DBI(::Loader) work stand-alone for you?

use Class::DBI::Loader;
my $loader = Class::DBI::Loader->new(
    dsn                     => "dbi:mysql:test",
    user                    => "root",
    password                => "",
    namespace               => "IsfdbMaypole",
    additional_classes      => qw/Class::DBI::AbstractSearch/,
    relationships           => 1
);

my $person = IsfdbMaypole::People->create({name => 'J. Doe'});
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