class_docstr: Non permanent document
  
  This document is meant for debugging purposes within the EphemeralDB.
  
  .. seealso:: :class:`orion.core.io.database.ephemeraldb.EphemeralDB` for database object.
class_docstr_tok: ["Non","permanent","document","This","document","is","meant","for","debugging","purposes","within","the","EphemeralDB",".","..","seealso",":",":",":","class",":","`","orion.core.io.database.ephemeraldb.EphemeralDB","`","for","database","object","."]
code: def _is_operator(self, key):
      return key.split(".")[-1].startswith("$")
  
imports: import copy
  from collections import defaultdict
  from orion.core.io.database import Database, DatabaseError, DuplicateKeyError
  from orion.core.utils.flatten import flatten, unflatten
label_desc: Use image node_id 3 for calling the EphemeralDocument obj's underlying member method code with example usage: obj._is_operator(key) and returns: key