{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "title": "Timestamp",
  "description": "An ISO 8601 combined date and time timestamp",
  "type": "string",
  "pattern": "^$|^[0-9]{4}-[0-1][0-9]-[0-3][0-9]T(2[0-3]|[01][0-9]):[0-5][0-9]:[0-5][0-9](Z|[+](2[0-3]|[01][0-9]):[0-5][0-9])$"
}