code: func (errs Errors) ToError() error {
  	if len(errs) == 0 {
  		return nil
  	}
  	if len(errs) == 1 {
  		return errs[0]
  	}
  	return errs
  }
docs: // ToError converts Errors to the error interface
  // returns nil if no errors are present, a single error object if only one is present