Code blocks in docstring are not fully rendered as sphinx doc.

The code blocks in the docstring are not rendered as expected int he sphinx doc.

The `code block` documentation In the following [example ](https://github.com/asyml/texar-pytorch/blob/master/texar/torch/run/executor.py#L613
)(and a few following), are not rendered correctly in the resulting [documentation](https://github.com/asyml/texar-pytorch/blob/master/texar/torch/run/executor.py#L613). Probably there is some slight indent mismatching here.

Inspect the docstring code blocks in texar/torch/run/executor.py around line 613 and compare them with the resulting Sphinx documentation linked in the issue. Check the indentation around the affected blocks, rebuild the documentation, and confirm that the examples render as code blocks.

Written by the indexing model from the issue text.