Get xgboost type parameters.

def get_xgb_params(self):
        """Get xgboost type parameters."""
        xgb_params = self.get_params()
        random_state = xgb_params.pop('random_state')
        if 'seed' in xgb_params and xgb_params['seed'] is not None:
            warnings.warn('The seed parameter is deprecated as of version .6.'
                          'Please use random_state instead.'
                          'seed is deprecated.', DeprecationWarning)
        else:
            xgb_params['seed'] = random_state
        n_jobs = xgb_params.pop('n_jobs')
        if 'nthread' in xgb_params and xgb_params['nthread'] is not None:
            warnings.warn('The nthread parameter is deprecated as of version .6.'
                          'Please use n_jobs instead.'
                          'nthread is deprecated.', DeprecationWarning)
        else:
            xgb_params['nthread'] = n_jobs

        if 'silent' in xgb_params and xgb_params['silent'] is not None:
            warnings.warn('The silent parameter is deprecated.'
                          'Please use verbosity instead.'
                          'silent is depreated', DeprecationWarning)
            # TODO(canonizer): set verbosity explicitly if silent is removed from xgboost,
            # but remains in this API
        else:
            # silent=None shouldn't be passed to xgboost
            xgb_params.pop('silent', None)

        if xgb_params['nthread'] <= 0:
            xgb_params.pop('nthread', None)
        return xgb_params