docstr: Unparse a single argument to a string.
docstr_tok: ["Unparse","a","single","argument","to","a","string","."]
code: def _visit_arg_with_default(
      self, arg: ast.arg, default: ast.AST | None
  ) -> str:
      """Unparse a single argument to a string."""
      name = self.visit(arg)
      if default:
          if arg.annotation:
              name += " = %s" % self.visit(default)
          else:
              name += "=%s" % self.visit(default)
      return name
  
imports: from __future__ import annotations
  import ast
  from typing import NoReturn, overload
label_desc: Use image node_id 4 for calling the _UnparseVisitor obj's underlying member method code with example usage: obj._visit_arg_with_default(arg, default) and returns: name