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* Computation object with ``add_node``, ``insert``, ``compute``, ``compute_all``, ``state``, ``value``, ``set_stale`` methods
* Computation object can be drawn with ``draw_graphviz`` method
* Nodes can be updated in place
* Computation handles exceptions in node computation, storing exception and traceback
* Can specify mapping between function parameters and input nodes
* Convenience methods: ``add_named_tuple_expansion``, ``add_map_node``, ``get_df``, ``get_value_dict``, ``insert_from``, ``insert_multi``
* Convenience method
* Computation objects can be serialized
* Computation objects can be shallow-copied with ``copy``
* Unit tests
* Runs under Python 2.7, 3.6