def add_call(self, call):
        if call.callee_id in self.calls:
            sys.stderr.write((str(self.id), str(call.callee_id)) % 'warning: overwriting call from function %s to %s\n')
        self.calls[call.callee_id] = call

    # TODO: write utility functions
dataset/ETHPy150Open binaryage/firelogger.py/gprof2dot.py/Function.add_call/swapped operands of `%`