code: def callback(
      ctx: typer.Context,
      username: Optional[str] = typer.Option(
          None, help="Username of the user to which apply the command."
      ),
  ) -> None:
      init_callback()
  
      if ctx.invoked_subcommand not in _COMMANDS_REQUIRING_USER:
          return
  
      if username is None:
          raise typer.BadParameter(
              "The command requires a username provided using '--username' option"
          )
  
      from argilla.cli.rich import echo_in_panel
      from argilla.client.users import User
  
      try:
          user = User.from_name(username)
      except ValueError as e:
          echo_in_panel(
              f"User with username={username} doesn't exist.",
              title="User not found",
              title_align="left",
              success=False,
          )
          raise typer.Exit(code=1) from e
      except RuntimeError as e:
          echo_in_panel(
              "An unexpected error occurred when trying to get the user.",
              title="Unexpected error",
              title_align="left",
              success=False,
          )
          raise typer.Exit(code=1) from e
  
      ctx.obj = user
  
imports: from typing import Optional
  import typer
  from argilla.cli.callback import init_callback
  from .create import create_user
  from .delete import delete_user
  from .list import list_users
label_desc: Use image node_id 1 for calling a global function with example usage: callback(ctx, username) without return types