code: def attention_bias_lower_triangle(length, bias_value=-1e18):
      """Create an bias tensor to be added to attention logits.
      Allows a query to attend to all positions up to and including its own.
  
      Args:
          length: a scalar.
  
      Returns:
          a `Tensor` with shape [1, 1, length, length].
      """
      return attention_bias_local(length, -1, 0, bias_value)
  
imports: import numpy
  import tensorflow
label_desc: Use image node_id 1 for calling a global function with example usage: attention_bias_lower_triangle(length, bias_value) and returns: attention_bias_local