code: def anchor_inside_flags(
      flat_anchors, valid_flags, img_shape, allowed_border=0
  ):
      """Check whether the anchors are inside the border.
  
      Args:
          flat_anchors (torch.Tensor): Flatten anchors, shape (n, 4).
          valid_flags (torch.Tensor): An existing valid flags of anchors.
          img_shape (tuple(int)): Shape of current image.
          allowed_border (int, optional): The border to allow the valid anchor.
              Defaults to 0.
  
      Returns:
          torch.Tensor: Flags indicating whether the anchors are inside a \
              valid range.
      """
      img_h, img_w = img_shape[:2]
      if allowed_border >= 0:
          inside_flags = (
              valid_flags
              & (flat_anchors[:, 0] >= -allowed_border)
              & (flat_anchors[:, 1] >= -allowed_border)
              & (flat_anchors[:, 2] < img_w + allowed_border)
              & (flat_anchors[:, 3] < img_h + allowed_border)
          )
      else:
          inside_flags = valid_flags
      return inside_flags
  
label_desc: Use image node_id 2 for calling a global function with example usage: anchor_inside_flags(flat_anchors, valid_flags, img_shape, allowed_border) and returns: inside_flags