get_message_content() returns None if content is audio

[THChen2002]

System Informations

• Python version:3.9.12
• SDK version:3.17.1
• OS:macOS

Expected Behavior

Calling get_message_content() should return a bytearray.

Current Behavior

Instead of returning a bytearray, get_message_content() returns None.
This issue occurs when the content type is mp3.
As a temporary workaround, I'm currently using get_message_content_with_http_info() to retrieve the content.

[mokuzon]

@THChen2002 Thanks for the bug report!
Unfortunately, I retrieved the Audio data with

line-bot-sdk-python/linebot/v3/messaging/api/messaging_api_blob.py

Lines 49 to 76 in 107447f

	@validate_arguments
	def get_message_content(self, message_id : Annotated[StrictStr, Field(..., description="Message ID of video or audio")], **kwargs) -> bytearray: # noqa: E501
	"""get_message_content # noqa: E501
	Download image, video, and audio data sent from users. # noqa: E501
	This method makes a synchronous HTTP request by default. To make an
	asynchronous HTTP request, please pass async_req=True
	>>> thread = api.get_message_content(message_id, async_req=True)
	>>> result = thread.get()
	:param message_id: Message ID of video or audio (required)
	:type message_id: str
	:param async_req: Whether to execute the request asynchronously.
	:type async_req: bool, optional
	:param _request_timeout: timeout setting for this request. If one
	number provided, it will be total request
	timeout. It can also be a pair (tuple) of
	(connection, read) timeouts.
	:return: Returns the result object.
	If the method is called asynchronously,
	returns the request thread.
	:rtype: bytearray
	"""
	kwargs['_return_http_data_only'] = True
	if '_preload_content' in kwargs:
	raise ValueError("Error! Please call the get_message_content_with_http_info method with `_preload_content` instead and obtain raw data from ApiResponse.raw_data")
	return self.get_message_content_with_http_info(message_id, **kwargs) # noqa: E501

in the same environment, and it worked fine, so I could not reproduce the bug.

Please provide a simple code to reproduce the bug.

[THChen2002]

Sorry about the description. The result will return None if I call get_message_content() after I got the audio message content. If I run it later, it can works. The following screenshot I provided is the situation.