code: def get(self, name, param=None):
          
          if name not in self.attribs:
              raise exceptions.SoftLayerError('Unknown metadata attribute.')
  
          call_details = self.attribs[name]
  
          if call_details.get('param_req'):
              if not param:
                  raise exceptions.SoftLayerError(
                      'Parameter required to get this attribute.')
  
          params = tuple()
          if param is not None:
              params = (param,)
          try:
              return self.client.call('Resource_Metadata',
                                      self.attribs[name]['call'],
                                      *params)
          except exceptions.SoftLayerAPIError as ex:
              if ex.faultCode == 404:
                  return None
              raise ex
docs: Retreive a metadata attribute.
  
          :param string name: name of the attribute to retrieve. See `attribs`
          :param param: Required parameter for some attributes