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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 index_next_crossing(value, array, starting_index=0, direction=1):
 """ starts at starting_index, and walks through the array until it finds a crossing point with value set direction=-1 for down crossing """


    for n in range(starting_index, len(array)-1):
        if  (value-array[n]  )*direction >= 0         \
        and (value-array[n+1])*direction <  0: return n

    # no crossing found
    return -1