Specifying raw type to `build_array()`

Hi,
I'm attempting to translate

sox -r {SAMPLE_RATE} -b {BITS} -e {ENCODING} -c {NUM_CHANNEL} -t raw  {raw_audio_file.name} {wav_audio_file.name}

to a call to build_array() but I can't seem to be able to specify the equivalent of -t raw.

Code

tfm2wav = sox.Transformer()
tfm2wav.set_input_format(
    file_type="raw",
    rate=SAMPLE_RATE,
    bits=BITS,
    channels=NUM_CHANNEL,
    encoding=ENCODING,
    )
tfm2wav.set_output_format(
      file_type="wav",
      rate=SAMPLE_RATE,
      bits=BITS,
      channels=NUM_CHANNEL,
      encoding=ENCODING,
      )

audio = tfm2wav.build_array(
    input_filepath=raw_audio_file.name,
    )
tfm2wav.build_file(
     input_array=audio,
     output_filepath=wav_audio_file.name,
     sample_rate_in=SAMPLE_RATE,
     )

Error Message

{
  "errorMessage": "list index out of range",
  "errorType": "IndexError",
  "requestId": "d89c028b-e894-4596-89fd-0a9f19017103",
  "stackTrace": [
    "  File \"/var/task/lambda_function.py\", line 103, in handler\n    raise e\n",
    "  File \"/var/task/lambda_function.py\", line 91, in handler\n    denoise(noisy_audio_file.name, denoised_audio_file.name)\n",
    "  File \"/var/task/lambda_function.py\", line 157, in denoise\n    audio = tfm2wav.build_array(\n",
    "  File \"/opt/python/sox/transform.py\", line 793, in build_array\n    encoding_out = [\n"
  ]
}

[ERROR]	2022-11-01T14:34:13.338Z	d89c028b-e894-4596-89fd-0a9f19017103	list index out of range

[ERROR] IndexError: list index out of range
Traceback (most recent call last):
  File "/var/task/lambda_function.py", line 103, in handler
    raise e
  File "/var/task/lambda_function.py", line 91, in handler
    denoise(noisy_audio_file.name, denoised_audio_file.name)
  File "/var/task/lambda_function.py", line 157, in denoise
    audio = tfm2wav.build_array(
  File "/opt/python/sox/transform.py", line 793, in build_array
    encoding_out = [END RequestId: d89c028b-e894-4596-89fd-0a9f19017103

Start in sox/transform.py at build_array around line 793, then trace how set_input_format handles file_type="raw" and how the supplied build_file path handles the same format. Reproduce the provided call and verify that raw input reaches build_array without the IndexError and can be converted to WAV.