human
Complete the below
def _validate(aString, firstOccurrenceOnly, loggedEvents, base, encoding, selfURIs=None):

    ''''validate RSS from string, returns validator object'
    '''

What is a the Python code you requested?
assistant
#Here is the Python code you requested.
    from xml.sax import make_parser, handler
    from base import SAXDispatcher
    from exceptions import UnicodeError
    from cStringIO import StringIO
    source = InputSource()
    source.setByteStream(StringIO(xmlEncoding.asUTF8(aString)))
    validator = SAXDispatcher(base, (selfURIs or [base]), encoding)
    validator.setFirstOccurrenceOnly(firstOccurrenceOnly)
    validator.loggedEvents += loggedEvents
    validator.setLiterals(re.findall('&#x26;(\\w+);', aString))
    xmlver = re.match('^<\\?\\s*xml\\s+version\\s*=\\s*[\'"]([-a-zA-Z0-9_.:]*)[\'"]', aString)
    if (xmlver and (xmlver.group(1) != '1.0')):
        validator.log(logging.BadXmlVersion({'version': xmlver.group(1)}))
    try:
        from xml.sax.expatreader import ExpatParser
        class fake_dtd_parser(ExpatParser, ):
            def reset(self):
                ExpatParser.reset(self)
                self._parser.UseForeignDTD(1)
        parser = fake_dtd_parser()
    except:
        parser = make_parser()
    parser.setFeature(handler.feature_namespaces, 1)
    parser.setContentHandler(validator)
    parser.setErrorHandler(validator)
    parser.setEntityResolver(validator)
    if hasattr(parser, '_ns_stack'):
        parser._ns_stack.append({'http://www.w3.org/XML/1998/namespace': 'xml'})
    def xmlvalidate(log):
        import libxml2
        from StringIO import StringIO
        from random import random
        prefix = ('...%s...' % str(random()).replace('0.', ''))
        msg = []
        libxml2.registerErrorHandler((lambda msg, str: msg.append(str)), msg)
        input = libxml2.inputBuffer(StringIO(xmlEncoding.asUTF8(aString)))
        reader = input.newTextReader(prefix)
        reader.SetParserProp(libxml2.PARSER_VALIDATE, 1)
        ret = reader.Read()
        while (ret == 1):
            ret = reader.Read()
        msg = ''.join(msg)
        for line in msg.splitlines():
            if line.startswith(prefix):
                log(line.split(':', 4)[(-1)].strip())
    validator.xmlvalidator = xmlvalidate
    try:
      ...