How to Sample data during Functional Coverage?

Coverage
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5

Thanks Dave. It’s still not working as expected. When I removed clocking block I got functional coverage as Zero (0)
covergroup covport @(ganglion_if.cb);

If I remove other clocking block , I get syntax error
Following verilog source has syntax error :
“test.sv”, 70: token is ‘(’
ck.sample();
^