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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_dot(stop=True):
 """Returns a string containing a DOT file. Setting stop to True will cause the trace to stop. """

    defaults = []
    nodes    = []
    edges    = []


    # define default attributes
    for comp, comp_attr in graph_attributes.items():
        attr = ', '.join( '%s = "%s"' % (attr, val)
                         for attr, val in comp_attr.items() )
        defaults.append( '\t%(comp)s [ %(attr)s ];\n' % locals() )

    # define nodes
    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)
        attribs = ['%s="%s"' % a for a in settings['node_attributes'].items()]
        node_str = '"%s" [%s];' % (func, ', '.join(attribs))
        nodes.append( node_str % locals() )

    # define edges
    for fr_key, fr_val in call_dict.items():
        if not fr_key: continue
        for to_key, to_val in fr_val.items():
            calls_frac, total_time_frac, totla_time = \
                _frac_calculation(to_key, to_val)
            col = settings['edge_colour'](calls_frac, total_time_frac)
            edge = '[ color = "%s", label="%s" ]' % (col, to_val)
            edges.append('"%s"->"%s" %s;' % (fr_key, to_key, edge))

    defaults = '\n\t'.join( defaults )
    nodes    = '\n\t'.join( nodes )
    edges    = '\n\t'.join( edges )

    dot_fmt = ("digraph G {\n"
               "	%(defaults)s\n\n"
               "	%(nodes)s\n\n"
               "	%(edges)s\n}\n"
              )
    return dot_fmt % locals()