import pathlib


def find_xml_files(*sources):
    """Yield full paths of xml files found in directories"""
    xmlfiles = list()
    for file in sources:
        file = pathlib.Path(file)
        if file.is_dir():
            for f in file.iterdir():
                if f.suffix.lower() == ".xml":
                    xmlfiles.append(f)
        else:
            xmlfiles.append(file)
    return xmlfiles