code: def unparse(node: ast.AST | None, code: str = "") -> str | None:
      """Unparse an AST to string."""
      if node is None:
          return None
      elif isinstance(node, str):
          return node
      return _UnparseVisitor(code).visit(node)
  
imports: from __future__ import annotations
  import ast
  from typing import NoReturn, overload
label_desc: Use image node_id 3 for calling a global function with example usage: unparse(node, code) and returns: _UnparseVisitor, None, node