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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_gdf(stop=True):
 """Returns a string containing a GDF file. Setting stop to True will cause the trace to stop. """

    ret = ['nodedef>name VARCHAR, label VARCHAR, hits INTEGER, ' + \
            'calls_frac DOUBLE, total_time_frac DOUBLE, ' + \
            'total_time DOUBLE, color VARCHAR, width DOUBLE']
    for func, hits in func_count.items():
        calls_frac, total_time_frac, total_time = _frac_calculation(func, hits)
        col = settings['node_colour'](calls_frac, total_time_frac)
        color = ','.join([str(round(float(c) * 255)) for c in col.split()])
        ret.append('%s,%s,%s,%s,%s,%s,\'%s\',%s' % (func, func, hits, \
                    calls_frac, total_time_frac, total_time, color, \
                    math.log(hits * 10)))
    ret.append('edgedef>node1 VARCHAR, node2 VARCHAR, color VARCHAR')
    for fr_key, fr_val in call_dict.items():
        if fr_key == '':
            continue
        for to_key, to_val in fr_val.items():
            calls_frac, total_time_frac, total_time = \
                _frac_calculation(to_key, to_val)
            col = settings['edge_colour'](calls_frac, total_time_frac)
            color = ','.join([str(round(float(c) * 255)) for c in col.split()])
            ret.append('%s,%s,\'%s\'' % (fr_key, to_key, color))
    ret = '\n'.join(ret)
    return ret