docs: def loadYAML (filename=None, data=None):
      """Loads either the given YAML configuration file or YAML data.
  
      Returns None if there was an error reading from the configuration
      file and logs an error message via ait.core.log.error().
      """
      config = None
  
      try:
          if filename:
              data = open(filename, 'rt')
  
          config = yaml.load(data)
  
          if type(data) is file:
              data.close()
      except IOError, e:
          msg = 'Could not read AIT configuration file "%s": %s'
          log.error(msg, filename, str(e))
  
      return config