code: def sigmoid_cross_entropy_with_logits(logits, targets):
    
    if logits.shape != targets.shape:
      raise ValueError(
          "logits shape must equal targets shape"
          "logits=%s targets=%s" % (logits.to_string, targets.to_string))
    x = logits
    z = targets
    return mtf.relu(x) - x * z + mtf.log(1 + mtf.exp(-mtf.abs(x)))
docs: Sigmoid cross-entropy loss.
  
    Args:
      logits: a mtf.Tensor
      targets: a mtf.Tensor with the same shape as logits
  
    Returns:
      a mtf.Tensor whose shape is equal to logits.shape
  
    Raises:
      ValueError: if the shapes do not match.