code: def mongo_host(env: Env) -> str:
      try:
          url = env.str(name="DATABASE_MIGRATIONS_MONGO_URL")
          if not isinstance(url, str):
              raise ValueError(
                  "DATABASE_MIGRATIONS_MONGO_URL is not set"
              )
          return url
      except Exception as e:
          raise ValueError(
              "DATABASE_MIGRATIONS_MONGO_URL is not set"
          ) from e
  
label_desc: Use image node_id 2 for calling a global function with example usage: mongo_host(env) and returns: url