code: def distance(latitude_1, longitude_1, latitude_2, longitude_2):
      
  
      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
docs: Distance between two points.