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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 expand(self,x,y,z):
 """ Expands the bounding """

        if x != None:
            if self.minx is None or x < self.minx:
                self.minx = x
            if self.maxx is None or x > self.maxx:
                self.maxx = x
        if y != None:
            if self.miny is None or y < self.miny:
                self.miny = y
            if self.maxy is None or y > self.maxy:
                self.maxy = y
        if z != None:
            if self.minz is None or z < self.minz:
                self.minz = z
            if self.maxz is None or z > self.maxz:
                self.maxz = z