code: def unset(self, x, y):
          
          x = normalize(x)
          y = normalize(y)
          col, row = get_pos(x, y)
  
          if type(self.chars[row][col]) == int:
              self.chars[row][col] &= ~pixel_map[y % 4][x % 2]
  
          if type(self.chars[row][col]) != int or self.chars[row][col] == 0:
              del(self.chars[row][col])
  
          if not self.chars.get(row):
              del(self.chars[row])
docs: Unset a pixel of the :class:`Canvas` object.
  
          :param x: x coordinate of the pixel
          :param y: y coordinate of the pixel