def __init__(self, state_machine, debug=0):
        """
        Initialize a `StateSM` object; extends `State.__init__()`.

        Check for indent state machine attributes, set defaults if not set.
        """
        State.__init__(self, state_machine, debug)
        if self.indent_sm is None:
            self.indent_sm = self.nested_sm
        if self.indent_sm_kwargs is None:
            self.indent_sm_kwargs = self.nested_sm_kwargs
        if self.known_indent_sm is None:
            self.known_indent_sm = self.indent_sm
        if self.known_indent_sm_kwargs is None:
            self.known_indent_sm_kwargs = self.indent_sm_kwargs