code: def shift(self, top=None, right=None, bottom=None, left=None):
          
          top = top if top is not None else 0
          right = right if right is not None else 0
          bottom = bottom if bottom is not None else 0
          left = left if left is not None else 0
          return self.copy(
              x1=self.x1+left-right,
              x2=self.x2+left-right,
              y1=self.y1+top-bottom,
              y2=self.y2+top-bottom
          )
docs: Shift the bounding box from one or more image sides, i.e. move it on the x/y-axis.
  
          Parameters
          ----------
          top : None or int, optional
              Amount of pixels by which to shift the bounding box from the top.
  
          right : None or int, optional
              Amount of pixels by which to shift the bounding box from the right.
  
          bottom : None or int, optional
              Amount of pixels by which to shift the bounding box from the bottom.
  
          left : None or int, optional
              Amount of pixels by which to shift the bounding box from the left.
  
          Returns
          -------
          result : imgaug.BoundingBox
              Shifted bounding box.