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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_lowpoints(node, dfs_data):
 """Calculates the lowpoints for a single node in a graph."""


    ordering_lookup = dfs_data['ordering_lookup']

    t_u = T(node, dfs_data)
    sorted_t_u = sorted(t_u, key=lambda a: ordering_lookup[a])
    lowpoint_1 = sorted_t_u[0]
    lowpoint_2 = sorted_t_u[1]

    return lowpoint_1, lowpoint_2