mutable struct AmrexCastro <: AbstractAmrex
  app::String
  degreesOfFreedom
  outputPrefix::String
  
  AmrexCastro() = new()
end

function init(extractor::AmrexCastro, outputPrefix::String)
  extractor.app = "AmrexCastro"
  extractor.degreesOfFreedom = [ 
            "max_step", 
            "amr.check_int",
            "amr.plot_int",
            "amr.n_cell",
            "amr.max_level",
            "castro.cfl", 
            "castro.max_grid_size"
        ]
  extractor.outputPrefix = outputPrefix
end