class_docstr: Non permanent collection
  
  This collection is meant for debugging purposes within the EphemeralDB.
  
  .. seealso:: :class:`orion.core.io.database.ephemeraldb.EphemeralDB` for database object.
class_docstr_tok: ["Non","permanent","collection","This","collection","is","meant","for","debugging","purposes","within","the","EphemeralDB",".","..","seealso",":",":",":","class",":","`","orion.core.io.database.ephemeraldb.EphemeralDB","`","for","database","object","."]
docstr: Initialise the collection, with no documents and only _id unique index.
docstr_tok: ["Initialise","the","collection",",","with","no","documents","and","only","_id","unique","index","."]
code: def __init__(self):
      """Initialise the collection, with no documents and only _id unique index."""
      self._documents = []
      self._indexes = {}
      self.create_index("_id", unique=True)
  
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 1 to create a new EphemeralCollection object  with example: obj = EphemeralCollection()