def get_param_value(params, key):
 try:
  return params[key]
 except KeyError:
  LOG.error(_LE('Request does not contain %s parameter!'), key)
  raise exception.HeatMissingParameterError(key)

def get_param_value ( params , key ) : try : return params [ key ] except KeyError : LOG . error ( _LE ( 'Request does not contain %s parameter!' ) , key ) raise exception . HeatMissingParameterError ( key )
looks up an expected parameter in a parsed params dict .