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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def update_fixed(self, kwargs_lens, kwargs_source, kwargs_lens_light, kwargs_ps, kwargs_cosmo, lens_add_fixed=[], source_add_fixed=[], lens_light_add_fixed=[], ps_add_fixed=[], cosmo_add_fixed=[], lens_remove_fixed=[], source_remove_fixed=[], lens_light_remove_fixed=[], ps_remove_fixed=[], cosmo_remove_fixed=[]):
 """ adds the values of the keyword arguments that are stated in the _add_fixed to the existing fixed arguments. :param kwargs_lens: :param kwargs_source: :param kwargs_lens_light: :param kwargs_ps: :param kwargs_cosmo: :param lens_add_fixed: :param source_add_fixed: :param lens_light_add_fixed: :param ps_add_fixed: :param cosmo_add_fixed: :return: updated kwargs fixed """

        lens_fixed = self._add_fixed(kwargs_lens, self._lens_fixed, lens_add_fixed)
        lens_fixed = self._remove_fixed(lens_fixed, lens_remove_fixed)
        source_fixed = self._add_fixed(kwargs_source, self._source_fixed, source_add_fixed)
        source_fixed = self._remove_fixed(source_fixed, source_remove_fixed)
        lens_light_fixed = self._add_fixed(kwargs_lens_light, self._lens_light_fixed, lens_light_add_fixed)
        lens_light_fixed = self._remove_fixed(lens_light_fixed, lens_light_remove_fixed)
        ps_fixed = self._add_fixed(kwargs_ps, self._ps_fixed, ps_add_fixed)
        ps_fixed = self._remove_fixed(ps_fixed, ps_remove_fixed)
        cosmo_fixed = copy.deepcopy(self._cosmo_fixed)
        for param_name in cosmo_add_fixed:
            if param_name in cosmo_fixed:
                pass
            else:
                cosmo_fixed[param_name] = kwargs_cosmo[param_name]
        for param_name in cosmo_remove_fixed:
            if param_name in cosmo_fixed:
                del cosmo_fixed[param_name]
                self._lens_fixed, self._source_fixed, self._lens_light_fixed, self._ps_fixed, self._cosmo_fixed = lens_fixed, source_fixed, lens_light_fixed, ps_fixed, cosmo_fixed