code: func (f *Function) removeVersions(versions []*lambda.FunctionConfiguration) error {
  	for _, v := range versions {
  		f.Log.Debugf("cleaning up version: %s", *v.Version)
  
  		_, err := f.Service.DeleteFunction(&lambda.DeleteFunctionInput{
  			FunctionName: &f.FunctionName,
  			Qualifier:    v.Version,
  		})
  
  		if err != nil {
  			return err
  		}
  	}
  
  	return nil
  }
docs: // removeVersions removes specifed function's versions