'Throws AssertionError if op is found'

def assertNotInBytecode(self, x, opname, argval=_UNSPECIFIED):

    for instr in dis.get_instructions(x):
        if (instr.opname == opname):
            disassembly = self.get_disassembly_as_string(x)
            if (argval is _UNSPECIFIED):
                msg = ('%s    occurs    in    bytecode:\n%s' % (opname, disassembly))
            elif (instr.argval == argval):
                msg = '(%s,%r)    occurs    in    bytecode:\n%s'
                msg = (msg % (opname, argval, disassembly))
            self.fail(msg)
