code: def filter_by_threshold(df, p_node_name_val, parent_threshold, side):
      """Filters the DataFrame by the threshold of the parent node.
  
      :param df: The DataFrame to filter.
      :type df: pandas.DataFrame
      :param p_node_name_val: The name of the parent node.
      :type p_node_name_val: str
      :param parent_threshold: The threshold of the parent node.
      :type parent_threshold: float
      :param side: The side of the parent node.
      :type side: TreeSide
      :return: The filtered DataFrame.
      :rtype: pandas.DataFrame
      """
      try:
          if side == TreeSide.LEFT_CHILD:
              df = df[df[p_node_name_val] <= parent_threshold]
          else:
              df = df[df[p_node_name_val] > parent_threshold]
          return df
      except TypeError as e:
          has_vals = df[p_node_name_val].shape[0] > 0
          if has_vals and isinstance(df[p_node_name_val][0], str):
              err = (
                  "Column {0} of type string is incorrectly treated "
                  "as numeric with threshold value {1}. "
                  "Please make sure it is marked as categorical instead."
              )
              err = err.format(p_node_name_val, parent_threshold)
              raise TypeError(err, e)
          else:
              raise e
  
imports: import logging
  import numbers
  from enum import Enum
  import numpy
  import pandas
  from lightgbm import Booster, LGBMClassifier, LGBMRegressor
  from sklearn.metrics import mean_absolute_error, mean_squared_error, median_absolute_error, r2_score
  from erroranalysis._internal.cohort_filter import filter_from_cohort
  from erroranalysis._internal.constants import DIFF, LEAF_INDEX, METHOD, PRED_Y, ROW_INDEX, SPLIT_FEATURE, SPLIT_INDEX, TRUE_Y, CohortFilterMethods, Metrics, ModelTask, TreeNode, error_metrics, f1_metrics, metric_to_display_name, precision_metrics, recall_metrics, regression_metrics
  from erroranalysis._internal.metrics import get_ordered_classes, metric_to_func
  from erroranalysis._internal.process_categoricals import process_categoricals
  from erroranalysis._internal.utils import is_spark
  from raiutils.exceptions import UserConfigValidationException
label_desc: Use image node_id 16 for calling a global function with example usage: filter_by_threshold(df, p_node_name_val, parent_threshold, side) and returns: df