code: def ls(ctx, input, indent, open_options):
      """
      List layers in a datasource.
      """
      result = fiona.listlayers(input, **open_options)
      click.echo(json.dumps(result, indent=indent))
  
imports: import json
  import click
  from cligj import indent_opt
  import fiona
  from fiona.fio import options, with_context_env
label_desc: Use image node_id 1 for calling a global function with example usage: ls(ctx, input, indent, open_options) without return types