code: func (c *ExpandSpec) Execute(args []string) error {
  	if len(args) != 1 {
  		return errors.New("The expand command requires the single swagger document url to be specified")
  	}
  
  	swaggerDoc := args[0]
  	specDoc, err := loads.Spec(swaggerDoc)
  	if err != nil {
  		return err
  	}
  
  	exp, err := specDoc.Expanded()
  	if err != nil {
  		return err
  	}
  
  	return writeToFile(exp.Spec(), !c.Compact, c.Format, string(c.Output))
  }
docs: // Execute expands the spec