code: def true_params(self):
      return np.concatenate(self.params[:-1])
  
imports: from statsmodels.compat.python import lrange
  import numpy
  from scipy import stats
  from statsmodels.genmod.generalized_estimating_equations import GEE, gee_setup_ordinal, gee_setup_nominal, gee_ordinal_starting_values, Multinomial
  from statsmodels.genmod.families import Binomial
  from statsmodels.genmod.cov_struct import GlobalOddsRatio
  from .gee_gaussian_simulation_check import GEE_simulator
label_desc: Use image node_id 2 for calling the nominal_simulator obj's underlying member method code with example usage: obj.true_params() and returns: np