code: func (o HostNetworkSystem) AddPortGroup(ctx context.Context, portgrp types.HostPortGroupSpec) error {
  	req := types.AddPortGroup{
  		This:    o.Reference(),
  		Portgrp: portgrp,
  	}
  
  	_, err := methods.AddPortGroup(ctx, o.c, &req)
  	if err != nil {
  		return err
  	}
  
  	return nil
  }
docs: // AddPortGroup wraps methods.AddPortGroup