api_keys.go
func (k APIKey) MarshalJSON() ([]byte, error) {
	// Approach for custom (un)marshalling borrowed from http://choly.ca/post/go-json-marshalling/
	type Alias APIKey
	return json.Marshal(&struct {
		Created *string `json:"created,omitempty"`
		*Alias
	}{
		Created: String(k.Created.Format(createdTimeLayout)),
		Alias:   (*Alias)(&k),
	})
}
func (k APIKey) MarshalJSON() ([]byte, error) {
	// Approach for custom (un)marshalling borrowed from http://choly.ca/post/go-json-marshalling/
	type Alias APIKey
	return json.Marshal(&struct {
		Created *string `json:"created,omitempty"`
		*Alias
	}{
		Created: String(k.Created.Format(createdTimeLayout)),
		Alias:   (*Alias)(&k),
	})
}
// MarshalJSON is a custom method for handling datetime marshalling