def VerifyDate(self, date, metatag):
    match = False
    if date:
      date = date.upper()
      for pattern in DATE_PATTERNS:
        match = pattern.match(date)
        if match:
          return True
      if not match:
        output.Warn('The value for %s does not appear to be in ISO8601 '
		    'format on URL: %s' % (metatag, self.loc))
        return False
  #end of VerifyDate
Verify the date format is valid
dataset/ETHPy150Open benoitc/restkit/doc/sitemap_gen.py/URL.VerifyDate