docs: def CheckFlowCanBeStartedOnClient(flow_name):
    """Checks if flow can be started on a particular client.
  
    Only flows with a category can bestarted. Having a category means that the
    flow will be accessible from the UI.
  
    Args:
      flow_name: Name of the flow to check access for.
  
    Returns:
      True if flow is externally accessible.
    Raises:
      access_control.UnauthorizedAccess: if flow is not externally accessible.
    """
    flow_cls = flow.GRRFlow.GetPlugin(flow_name)
  
    if flow_cls.category:
      return True
    else:
      raise access_control.UnauthorizedAccess(
          "Flow %s can't be started on a client by non-suid users." % flow_name)