pub const HAS_TIMESTAMP: &str = "https://github.com/DataTreehouse/chrontext#hasTimestamp";
pub const HAS_TIMESERIES: &str = "https://github.com/DataTreehouse/chrontext#hasTimeseries";
pub const HAS_DATA_POINT: &str = "https://github.com/DataTreehouse/chrontext#hasDataPoint";
pub const HAS_VALUE: &str = "https://github.com/DataTreehouse/chrontext#hasValue";
pub const HAS_RESOURCE: &str = "https://github.com/DataTreehouse/chrontext#hasResource";
pub const HAS_EXTERNAL_ID: &str = "https://github.com/DataTreehouse/chrontext#hasExternalId";
pub const NEST: &str = "https://github.com/DataTreehouse/chrontext#nestAggregation";
pub const GROUPING_COL: &str = "grouping_col";

