A strategy helps a minimizer in some situations - such as when encountering NaNs - and hooks into the loss evaluation. They can be used to create a

Strategies

zfit.minimize.PushbackStrategy()	Pushback by adding nan_penalty * counter to the loss if NaNs are encountered.
zfit.minimize.DefaultStrategy	alias of PushbackStrategy
zfit.minimize.DefaultToyStrategy()	Same as PushbackStrategy, but does not raise an error on full failure, instead return an invalid FitResult.