class_docstr: Singleton class that counts how much __init__ and count was called.
code: def __init__(self):
      self.counter += 1
  
file_path: airflow/tests/utils/test_singleton.py
imports: from __future__ import annotations
  from airflow.utils.singleton import Singleton
label_desc: Use image node_id 1 to create a new Counter object  with example: obj = Counter()