code: def prepare_solver(
      solver, X, y, fit_intercept=True, model="logistic", prox="l2"
  ):
      if model == "logistic":
          model = ModelLogReg(fit_intercept=fit_intercept).fit(X, y)
      elif model == "poisson":
          model = ModelPoisReg(fit_intercept=fit_intercept).fit(X, y)
      solver.set_model(model)
      if prox == "l2":
          l_l2sq = TestSolver.l_l2sq
          prox = ProxL2Sq(l_l2sq, (0, model.n_coeffs))
      if prox is not None:
          solver.set_prox(prox)
  
file_path: tick/tick/solver/tests/solver.py
imports: import unittest
  import itertools
  import numpy
  from scipy.linalg import norm
  from scipy.sparse import csr_matrix
  from tick.linear_model import ModelLogReg, ModelPoisReg, ModelLinReg, SimuLinReg, SimuLogReg, SimuPoisReg
  from tick.prox import ProxL2Sq, ProxZero, ProxL1
  from tick.solver import SVRG, AGD, SGD, SDCA, GD, BFGS, AdaGrad
  from tick.simulation import weights_sparse_gauss
label_desc: Use image node_id 4 for calling the TestSolver obj's underlying member method code with example usage: obj.prepare_solver(solver, X, y, fit_intercept, model, prox) without return types