from lxml import etree
schema = etree.XMLSchema(file='mzML1.1.0.xsd')
try:
    parser = etree.iterparse(open(r'D:\files\average.mzML'), schema=schema)
    for element in parser:
        print element
except etree.XMLSyntaxError, e:
    print e.position
    print e.lineno
    print e.error_log
    raise