class_docstr: Represents an environment variable.
code: def __format__(self, format_spec: str) -> str:
      return self.name.__format__(format_spec)
  
file_path: mlflow/mlflow/environment_variables.py
imports: import os
  from pathlib import Path
label_desc: Use image node_id 9 for calling the _EnvironmentVariable obj's underlying member method code with example usage: obj.__format__(format_spec) and returns: self