code: def list_keys(pymux, variables):
      
      # Create help string.
      result = []
  
      for k, custom_binding in pymux.key_bindings_manager.custom_bindings.items():
          needs_prefix, key = k
  
          result.append('bind-key %3s %-10s %s %s' % (
              ('-n' if needs_prefix else ''), key, custom_binding.command,
              ' '.join(map(wrap_argument, custom_binding.arguments))))
  
      # Display help in pane.
      result = '\n'.join(sorted(result))
      pymux.get_client_state().layout_manager.display_popup('list-keys', result)
docs: Display all configured key bindings.