ValueError: List argument ‘indices’ to ‘Sparse Concat’ Op with length 0 shorter than minimum length 2.

This error message is related to the TensorFlow library and occurs when you try to concatenate sparse tensors using the "Sparse Concat" operation, but the "indices" argument provided has a length of 0 or 1.

The "Sparse Concat" operation requires at least two sparse tensors to be concatenated, and the "indices" argument specifies the indices of the non-zero elements in each sparse tensor. If this argument has a length of 0 or 1, it means that there are not enough non-zero elements in the sparse tensors to perform the concatenation.

To fix this error, you need to make sure that the sparse tensors you are trying to concatenate have a sufficient number of non-zero elements. You can also check the length of the "indices" argument to ensure that it has a minimum length of 2.