How to use the gprof2dot.DotWriter function in gprof2dot

parser = Format(args[0])

    profile = parser.parse()

    if options.output is None:
        if PYTHON_3:
            output = open(sys.stdout.fileno(), mode='wt', encoding='UTF-8', closefd=False)
        else:
            output = sys.stdout
    else:
        if PYTHON_3:
            output = open(options.output, 'wt', encoding='UTF-8')
        else:
            output = open(options.output, 'wt')

    dot = DotWriter(output)
    dot.strip = options.strip
    dot.wrap = options.wrap

    labelNames = options.node_labels or defaultLabelNames
    dot.show_function_events = [labels[l] for l in labelNames]
    if options.show_samples:
        dot.show_function_events.append(SAMPLES)

    profile = profile
    profile.prune(options.node_thres/100.0, options.edge_thres/100.0, options.filter_paths, options.color_nodes_by_selftime)

    if options.root:
        rootIds = profile.getFunctionIds(options.root)
        if not rootIds:
            sys.stderr.write('root node ' + options.root + ' not found (might already be pruned : try -e0 -n0 flags)\n')
            sys.exit(1)

def _create_dot(profile, cutoff):
    """
    Create a dot file from pstats data stored in a django file field.
    """
    node_cutoff = cutoff / 100.0
    edge_cutoff = 0.1 / 100.0
    profile.prune(node_cutoff, edge_cutoff, [], False)

    with closing(StringIO()) as fp:
        DotWriter(fp).graph(profile, COLOR_MAP)
        return fp.getvalue()

def __rungprof2dot(self):
        """Runs gprof2dot which produces a full dot spec"""
        nodeLimit = Settings().getProfilerSettings().nodeLimit
        edgeLimit = Settings().getProfilerSettings().edgeLimit
        with io.StringIO() as buf:
            gprofParser = gprof2dot.PstatsParser(self.__dataFile)
            profileData = gprofParser.parse()
            profileData.prune(nodeLimit / 100.0, edgeLimit / 100.0, False, False)

            dot = gprof2dot.DotWriter(buf)
            dot.strip = False
            dot.wrap = False
            dot.graph(profileData, gprof2dot.TEMPERATURE_COLORMAP)

            output = buf.getvalue()
        return self.__postprocessFullDotSpec(output)

caller.add_call(call)
                else:
                    call[SAMPLES2] += alloc.size

                callee = caller

        # compute derived data
        profile.validate()
        profile.find_cycles()
        profile.ratio(TIME_RATIO, SAMPLES)
        profile.call_ratios(SAMPLES2)
        profile.integrate(TOTAL_TIME_RATIO, TIME_RATIO)

        from gprof2dot import DotWriter, TEMPERATURE_COLORMAP

        writer = DotWriter(open('memtrail.dot', 'wt'))
        writer.strip = True
        writer.wrap = True
        profile.prune(0.5/100.0, 0.1/100.0)
        writer.graph(profile, TEMPERATURE_COLORMAP)