#!/usr/bin/python -u
import libxml2


rngp = libxml2.relaxNGNewParserCtxt("ex4.rng")
rngs = rngp.relaxNGParse()

reader = libxml2.newTextReaderFilename("ex4.xml")
reader.RelaxNGSetSchema(rngs)
ret = reader.Read()
while ret == 1:
    ret = reader.Read()

if ret != 0:
    print "Error parsing the document"

if reader.IsValid() == 1:
    print "Document validates"