code: func (s *StaticProvider) Retrieve() (Value, error) {
  	if s.Token == "" {
  		return Value{ProviderName: StaticCredentialsProviderName},
  			ErrStaticCredentialsEmpty
  	}
  	if len(s.Value.ProviderName) == 0 {
  		s.Value.ProviderName = StaticCredentialsProviderName
  	}
  	return s.Value, nil
  }
docs: // Retrieve returns the credentials or error if the credentials are invalid.