SLACK_TOKEN = XXX
slack_client = slack_sdk.WebClient(SLACK_TOKEN)
slack_client.files_upload_v2(channel="test", content="test")

        filename: Optional[str] = None,  # you can skip this only when sending along with content parameter

slack_sdk.errors.SlackApiError: The request to the Slack API failed. (url: https://www.slack.com/api/files.getUploadURLExternal)
The server responded with: {'ok': False, 'error': 'invalid_arguments', 'response_metadata': {'messages': ['[ERROR] missing required field: filename']}}

def _to_v2_file_upload_item(upload_file: Dict[str, Any]) -> Dict[str, Optional[Any]]:
    ...
    filename = upload_file.get("filename")
    if upload_file.get("filename") is None and isinstance(file, str):
        # use the local filename if filename is missing
        if upload_file.get("filename") is None:  # <- this will always be true
            filename = file.split(os.path.sep)[-1]
        else:
            filename = "Uploaded file"

def _to_v2_file_upload_item(upload_file: Dict[str, Any]) -> Dict[str, Optional[Any]]:
    ...
    filename = upload_file.get("filename")
    if filename is None:
        if isinstance(file, str):
            # use the local filename if filename is missing
            filename = file.split(os.path.sep)[-1]
        else:
            filename = "Uploaded file"