code: def get_current(cls):
          
          filepath = os.getenv("REZ_RXT_FILE")
          if not filepath or not os.path.exists(filepath):
              return None
  
          return cls.load(filepath)
docs: Get the context for the current env, if there is one.
  
          Returns:
              `ResolvedContext`: Current context, or None if not in a resolved env.