code: def _build_instance_group_args(self, instance_group):
          
          params = {
              'InstanceCount' : instance_group.num_instances,
              'InstanceRole' : instance_group.role,
              'InstanceType' : instance_group.type,
              'Name' : instance_group.name,
              'Market' : instance_group.market
          }
          if instance_group.market == 'SPOT':
              params['BidPrice'] = instance_group.bidprice
          return params
docs: Takes an InstanceGroup; returns a dict that, when its keys are
          properly prefixed, can be used for describing InstanceGroups in
          RunJobFlow or AddInstanceGroups requests.