def FitVariable(self, vardict):
        """
        Add one or more variables to the list being fit.

        :param vardict: a dictionary where the key is the parameter
                     name and the value is the initial guess for that parameter.
                     Valid parameter names can be found by invoking
                     DisplayVariables(fitonly=False)

        :return: None
        """
        for par in vardict.keys():
            try:
                idx = self.parnames.index(par)
                if par is not ['wavestart', 'waveend'] and isinstance(vardict[par], u.quantity.Quantity):
                    # Convert to nanometers
                    vardict[par] = vardict[par].to(u.nm).value
                self.const_pars[idx] = vardict[par]
                self.fitting[idx] = True
            except ValueError:
                print("Error! Bad parameter name given. Currently available are: ")
                self.DisplayVariables()
                raise ValueError


            ### -----------------------------------------------
dataset/ETHPy150Open kgullikson88/Telluric-Fitter/src/TelluricFitter.py/TelluricFitter.FitVariable/operator `in` -> `is not`