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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 distance(latitude_1, longitude_1, latitude_2, longitude_2):
 """ Distance between two points. """


    coef = mod_math.cos(latitude_1 / 180. * mod_math.pi)
    x = latitude_1 - latitude_2
    y = (longitude_1 - longitude_2) * coef

    return mod_math.sqrt(x * x + y * y) * ONE_DEGREE