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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 rectangle(self, x, y, width, height, corner_radius = 0):
 """draw a rectangle. if corner_radius is specified, will draw rounded corners. corner_radius can be either a number or a tuple of four items to specify individually each corner, starting from top-left and going clockwise"""

        if corner_radius <= 0:
            self._add_instruction("rectangle", x, y, width, height)
            return

        # convert into 4 border and  make sure that w + h are larger than 2 * corner_radius
        if isinstance(corner_radius, (int, float)):
            corner_radius = [corner_radius] * 4
        corner_radius = [min(r, min(width, height) / 2) for r in corner_radius]

        x2, y2 = x + width, y + height
        self._rounded_rectangle(x, y, x2, y2, corner_radius)