code: def test_low_memory_warm_start():
      """Check the warm_start functionality works as expected with low_memory."""
  
      est = SymbolicRegressor(
          population_size=50,
          generations=20,
          random_state=415,
          low_memory=True,
      )
      est.fit(diabetes.data, diabetes.target)
      cold_fitness = est._program.fitness_
      cold_program = est._program.__str__()
  
      # Check warm start with low memory gets the same result
      est = SymbolicRegressor(
          population_size=50,
          generations=10,
          random_state=415,
          low_memory=True,
      )
      est.fit(diabetes.data, diabetes.target)
      est.set_params(generations=20, warm_start=True)
      est.fit(diabetes.data, diabetes.target)
      warm_fitness = est._program.fitness_
      warm_program = est._program.__str__()
      assert_almost_equal(cold_fitness, warm_fitness)
      assert cold_program == warm_program
  
imports: import pickle
  import pytest
  import sys
  from io import StringIO
  import numpy
  from scipy.stats import pearsonr, spearmanr
  from sklearn.datasets import load_diabetes, load_breast_cancer
  from sklearn.metrics import mean_absolute_error
  from sklearn.model_selection import GridSearchCV
  from sklearn.pipeline import make_pipeline
  from sklearn.preprocessing import StandardScaler
  from sklearn.tree import DecisionTreeRegressor
  from sklearn.utils._testing import assert_almost_equal
  from sklearn.utils._testing import assert_array_equal
  from sklearn.utils._testing import assert_array_almost_equal
  from sklearn.utils._testing import assert_raises
  from sklearn.utils.validation import check_random_state
  from gplearn.genetic import SymbolicClassifier, SymbolicRegressor
  from gplearn.genetic import SymbolicTransformer
  from gplearn.fitness import weighted_pearson, weighted_spearman
  from gplearn._program import _Program
  from gplearn.fitness import _fitness_map
  from gplearn.functions import add2, sub2, mul2, div2, sqrt1, log1, abs1, max2, min2
  from gplearn.functions import _Function
label_desc: Use image node_id 35 for calling a global function with example usage: test_low_memory_warm_start() without return types