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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 round_corner(radius, fill):
 """Draw a round corner"""

    corner = Image.new('L', (radius, radius), 0)  # (0, 0, 0, 0))
    draw = ImageDraw.Draw(corner)
    draw.pieslice((0, 0, radius * 2, radius * 2), 180, 270, fill=fill)
    return corner