code: def missing_attr(
      c,
      a,  # type: str
      b=None,  # type: Optional[str]
  ):
      # type: (...) -> str
      return a + (b or "")
  
imports: from __future__ import annotations
  import pathlib
  from typing import Any, Tuple, TypeVar, Union
label_desc: Use image node_id 5 for calling a global function with example usage: missing_attr(c, a, b) and returns: unknown