var DateTimeAliases … // ValidAlias checks to make sure the given alias is a valid one func ValidAlias(alias string) bool { … } type PollutionParameters … type Pollution … type PollutionData … // NewPollution creates a new reference to Pollution func NewPollution(key string, options ...Option) (*Pollution, error) { … } // PollutionByParams gets the pollution data based on the given parameters func (p *Pollution) PollutionByParams(params *PollutionParameters) error { … }