How to add two encoding type together as parameter while xml parsing?

Question

One xml file has encoding type UTF-16 and another has UTF-8. After taking input of two files I want to parse it together, How to add two encoding type?

tree = ET.parse(xmlFile)
xml_data = tree.getroot()
xmlstr = ET.tostring(xml_data, encoding='utf-8/UTF-16', method='xml')
data_dict = dict(xmltodict.parse(xmlstr))