from lxml import etree

xml_file = 'teste.mmp'
xsd_file = 'mmp.xsd'

with open(xsd_file, 'rb') as f:
    schema_doc = etree.XML(f.read())
schema = etree.XMLSchema(schema_doc)

with open(xml_file, 'rb') as f:
    doc = etree.XML(f.read())

if schema.validate(doc):
    print("XML válido!")
else:
    print("XML inválido!")
    print(schema.error_log)