code: def lower_triangular_ones(F, d: int, offset: int = 0) -> Tensor:
      """
      Constructs a lower triangular matrix consisting of ones.
  
      Parameters
      ----------
      F
      d
          Dimension of the output tensor, whose shape will be (d, d).
      offset
          Indicates how many diagonals to set to zero in the lower triangular
          part. By default, offset = 0, so the output matrix contains also the
          main diagonal. For example, if offset = 1 then the output will be a
          strictly lower triangular matrix (i.e. the main diagonal will be zero).
  
      Returns
      -------
      Tensor
          Tensor of shape (d, d) consisting of ones in the strictly lower
          triangular part, and zeros elsewhere.
      """
      mask = F.zeros_like(F.eye(d))
      for k in range(offset, d):
          mask = mask + F.eye(d, d, -k)
      return mask
  
imports: from typing import Optional, Type
  import mxnet
  import numpy
  from gluonts.mx import Tensor
label_desc: Use image node_id 2 for calling a global function with example usage: lower_triangular_ones(F, d, offset) and returns: mask