A series has an invalid observation (".")
The series CSO/TSA07/TSA07C2.EU272020 has an observation value of "."
which is invalid, in json-data.
Corresponding source-data file is https://git.nomics.world/dbnomics-source-data/cso-source-data/-/blob/master/TSA07.json
Cf https://api.db.nomics.world/v22/series/CSO/TSA07/TSA07C2.EU272020?observations=1