In the winter, municipal snowplows must plow both sides of city streets that are bidirectional (two-way traffic) but they only make a single pass over unidirectional (one-way) streets. We can represent city streets as the edges in a graph using nodes for intersections. Of course, it is a requirement that every street be plowed appropriately (once in each direction for bidirectional streets and only once in the proper direction for unidirectional streets). Write a program that uses integers to represent nodes, and tuples (pairs of integers enclosed in parentheses, e.g., (4 7), to represent a street from node 4 to node 7, and a second tuple, (7 4) to represent the fact that this is a bidirectional street). Assume that there is but a single snowplow and it must start and return to node 1. Your program must read a collection of tuples from a file and then produce driving instructions for the snowplow operator telling the sequence of intersections (nodes) to visit so that all the streets are appropriatel