arg argument_spec: Dictionary of parameters, their type, and valid values.
    :arg parameters: Dictionary of parameters.
    :arg legal_inputs: List of valid key names property names. Overrides values
        in argument_spec.
    :arg options_context: List of parent keys for tracking the context of where
        a parameter is defined.

    :returns: Set of unsupported parameters. Empty set if no unsupported parameters
        are found.
    )r„