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A fallback activity may be defined to run if the activity under which it is defined fails. This can be used to run a simple module if the more complex method used in preference fails, and ensures continuity of the forecasting process. The definition of the fallbackActivity is the same as the definition of an activity. A fallback activity cannot be used to turn a partly completed (completed with errors) TaskRun into a fully successful TaskRun (complete without errors).
ensemble
This element is defined to indicate the activity is to run as an ensemble.
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