#268 Update aggregate_region so it can find variables below sub-cateogories too
#267 Make clear error message if variable-region pair is missing when check_aggregate_region is called
#261 Add a check that keep in filter() is a boolean
#254 Hotfix for aggregating missing regions and filtering empty dataframes
#243 Update pyam.iiasa.Connection to support all public and private database connections. DEPRECATED: the argument 'iamc15' has been deprecated in favor of names as queryable directly from the REST API.