AttributeError when converts IF to json

[zhilix]

I built the repo and ran the command trying to convert a physical netlist IF to a .json file:

    --schema_dir "/home/local/eda15/zhilix/projects/RapidWright/interchange/fpga-interchange-schema/interchange" \
    --schema physical \
    --input_format capnp \
    --output_format json \
    FPGA01_postroute_interchange.phys \
    FPGA01_postroute_interchange.json

But I got error message like this:

  File "/home/polaris/zhilix/.pyenv/versions/3.8.4/lib/python3.8/runpy.py", line 194, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/home/polaris/zhilix/.pyenv/versions/3.8.4/lib/python3.8/runpy.py", line 87, in _run_code
    exec(code, run_globals)
  File "/home/local/eda15/zhilix/projects/python-fpga-interchange/fpga_interchange/convert.py", line 208, in <module>
    main()
  File "/home/local/eda15/zhilix/projects/python-fpga-interchange/fpga_interchange/convert.py", line 201, in main
    message = read_format(schema, args.input_format, in_f)
  File "/home/local/eda15/zhilix/projects/python-fpga-interchange/fpga_interchange/convert.py", line 105, in read_format
    message = message.as_builder()
AttributeError: '_GeneratorContextManager' object has no attribute 'as_builder'

This is due to the from_bytes() in pycapnp library:
https://github.com/capnproto/pycapnp/issues/287