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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 set_back(self, x: int, y: int, r: int, g: int, b: int) -> None: """Set the background color of one cell. Args: x (int):
 X position to change. y (int):
 Y position to change. r (int):
 Red background color, from 0 to 255. g (int):
 Green background color, from 0 to 255. b (int):
 Blue background color, from 0 to 255. """

        i = self.width * y + x
        self.back_r[i] = r
        self.back_g[i] = g
        self.back_b[i] = b