Вот подробная документация и исходный код:
https://github.com/trinath503/Python/tree/master/Generate_Pascal_VOC_Files
ПРИМЕЧАНИЕ. Вам необходимо передать данные в указанном формате
pascal_voc_data = '''
[
{
"folder":"folder",
"filename": "1.jpg",
"path":"path",
"source":{"database":"database"},
"size":{"width":256,"height":256,"depth":3},
"segmented":0,
"objects":[{"name":"name","pose":"pose","truncated":"truncated","occluded":"occluded","bndbox":{"xmin":3,"xmax":33,"ymin":3,"ymax":33}},{"name":"name","pose":"pose","truncated":"truncated","occluded":"occluded","bndbox":{"xmin":3,"xmax":33,"ymin":3,"ymax":33}}]
},
{
"folder":"folder",
"filename": "2.jpg",
"path":"path",
"source":{"database":"database"},
"size":{"width":256,"height":256,"depth":3},
"segmented":0,
"objects":[{"name":"name","pose":"pose","truncated":"truncated","occluded":"occluded","bndbox":{"xmin":3,"xmax":33,"ymin":3,"ymax":33}},{"name":"name","pose":"pose","truncated":"truncated","occluded":"occluded","bndbox":{"xmin":3,"xmax":33,"ymin":3,"ymax":33}}]
}
]
'''