code: def design_mat_info():
      """Training data in design matrix form"""
      x1 = np.array([1, 2, 3, 4, 5])
      x2 = 2 * x1
      x3 = np.array([1, 3, 5, 11, 12])
      y = 10 + 0 * x1 + 2 * x2 + 4 * x3
  
      df = pd.DataFrame({"y": y, "x1": x1, "x2": x2, "x3": x3})
      model_formula_str = "y ~ x1 + x2 + x3"
      return design_mat_from_formula(
          df, model_formula_str, pred_cols=None, y_col=None
      )
  
imports: import warnings
  import numpy
  import pandas
  import pytest
  import scipy
  from pandas.testing import assert_frame_equal
  from patsy import dmatrices
  from greykite.algo.common.ml_models import breakdown_regression_based_prediction
  from greykite.algo.common.ml_models import design_mat_from_formula
  from greykite.algo.common.ml_models import fit_ml_model
  from greykite.algo.common.ml_models import fit_ml_model_with_evaluation
  from greykite.algo.common.ml_models import fit_model_via_design_matrix
  from greykite.algo.common.ml_models import get_h_mat
  from greykite.algo.common.ml_models import get_intercept_col_from_design_mat
  from greykite.algo.common.ml_models import predict_ml
  from greykite.algo.common.ml_models import predict_ml_with_uncertainty
  from greykite.algo.uncertainty.conditional.conf_interval import predict_ci
  from greykite.common.constants import ERR_STD_COL
  from greykite.common.constants import QUANTILE_SUMMARY_COL
  from greykite.common.constants import TimeFeaturesEnum
  from greykite.common.evaluation import EvaluationMetricEnum
  from greykite.common.evaluation import calc_pred_err
  from greykite.common.features.timeseries_features import build_time_features_df
  from greykite.common.features.timeseries_features import fourier_series_multi_fcn
  from greykite.common.features.timeseries_features import get_fourier_col_name
  from greykite.common.python_utils import assert_equal
  from greykite.common.testing_utils import gen_sliced_df
label_desc: Use image node_id 1 for calling a global function with example usage: design_mat_info() and returns: design_mat_from_formula