You're reblessing your object into the wrong class. No wonder Perl can't find your method.

$self = $defaults->{'object'};
...
bless $self, $class;
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I'm not sure what you intend to do with those lines, but they don't have the desired effect.

Similarly:

UNIVERSAL::isa($defaults->{'object'},'My::New::Module')

... is correct only in very simple circumstances. It's more correct to write:

$defaults->{object}->isa( 'My::New::Module' )

... but then again, it's not clear what you intend this code to do.