Here's a concrete example that worked for me, using the Decimal class. I expect the usage to be analogous for the Hyperdex library. As Anony-Monk pointed out, the do-it-yourselfer's guide is valuable documentation here.
use Inline::Python qw(py_eval py_call_function);
py_eval("import decimal");
my $d1 = Inline::Python::Object->new('decimal', 'Decimal', '42.00');
my $d2 = Inline::Python::Object->new('decimal', 'Decimal', '2.00');
my $d3 = $d1->__mul__($d2);
print $d3->to_eng_string();
# prints "84.000"