As said in the doc, there's a flag named builtin in Filtering session, but I still can't get it tracing open() calls with the following snippet.
import hunter
hunter.trace(hunter.Q(builtin=True, function="open", action=hunter.CallPrinter))
f = open("test_trace.py", "r")
lines = f.readlines()
print(lines[0])
f.close()