def add_obj_to_selection(self, obj):
        """Add object to selection, if not selected already.

        Also makes the object the active one.

        Parameters
        ==========
        obj
        ( graphman.callablenode.CallableNode (or subclass)
          or graphman.textblock.TextBlock
          or graphman.proxynode.ProxyNode
          or graphman.proxynode.OperatorNode instance
        )
            obj to be added to selection.
        """
        if obj not in self.selected_objs:
            self.selected_objs.append(obj)

        self.active_obj = obj
Add object to selection, if not selected already.

        Also makes the object the active one.

        Parameters
        ==========
        obj
        ( graphman.callablenode.CallableNode (or subclass)
          or graphman.textblock.TextBlock
          or graphman.proxynode.ProxyNode
          or graphman.proxynode.OperatorNode instance
        )
            obj to be added to selection.
        
nodezator/editing/selection.py