How to use the gprof2dot.Call function in gprof2dot

fields = line.split()
            samples = float(fields[0])
            callstack = fields[1:]

            callstack = [self.symbols[symbol_id] for symbol_id in callstack]

            callee = callstack[0]

            callee[SAMPLES] += samples
            self.profile[SAMPLES] += samples
            
            for caller in callstack[1:]:
                try:
                    call = caller.calls[callee.id]
                except KeyError:
                    call = Call(callee.id)
                    call[SAMPLES2] = samples
                    caller.add_call(call)
                else:
                    call[SAMPLES2] += samples

                callee = caller

position = int(position)
            self.last_positions[i] = position

        events = [float(event) for event in events]

        if calls is None:
            function[SAMPLES] += events[0] 
            self.profile[SAMPLES] += events[0]
        else:
            callee = self.get_callee()
            callee.called += calls
    
            try:
                call = function.calls[callee.id]
            except KeyError:
                call = Call(callee.id)
                call[CALLS] = calls
                call[SAMPLES2] = events[0]
                function.add_call(call)
            else:
                call[CALLS] += calls
                call[SAMPLES2] += events[0]

        self.consume()
        return True