flat_field step has the following optional arguments to control
the behavior of the processing.
A flag to indicate whether to save to a file the NIRSpec flat field that was constructed on-the-fly by the step. Only relevant for NIRSpec data.
The name of a user-supplied flat-field reference file.
A flag to indicate whether the math operations used to apply the flat-field should be inverted (i.e. multiply the flat-field into the science data, instead of the usual division).