code: def cumsum(x: Tensor, dim: int = 0) -> Tensor:
      r"""Returns the cumulative sum of elements of :obj:`x`.
      In contrast to :meth:`torch.cumsum`, prepends the output with zero.
  
      Args:
          x (torch.Tensor): The input tensor.
          dim (int, optional): The dimension to do the operation over.
              (default: :obj:`0`)
  
      Example:
          >>> x = torch.tensor([2, 4, 1])
          >>> cumsum(x)
          tensor([0, 2, 6, 7])
  
      """
      size = x.size()[:dim] + (x.size(dim) + 1,) + x.size()[dim + 1 :]
      out = x.new_empty(size)
  
      out.narrow(dim, 0, 1).zero_()
      torch.cumsum(x, dim=dim, out=out.narrow(dim, 1, x.size(dim)))
  
      return out
  
label_desc: Use image node_id 1 for calling a global function with example usage: cumsum(x, dim) and returns: out