code: def _flatten_numpydoc_rules(rules):
      flattened = []
      for rule in rules:
          flattened.extend(filter(None, rule.split(",")))
      return flattened
  
imports: from collections import namedtuple
  from io import StringIO
  import click
  import json
  import logging
  import os
  import pathlib
  import sys
  from .benchmark.codec import JsonEncoder
  from .benchmark.compare import RunnerComparator, DEFAULT_THRESHOLD
  from .benchmark.runner import CppBenchmarkRunner, JavaBenchmarkRunner
  from .compat import _import_pandas
  from .lang.cpp import CppCMakeDefinition, CppConfiguration
  from .utils.cli import ArrowBool, validate_arrow_sources, add_optional_command
  from .utils.lint import linter, python_numpydoc, LintValidationException
  from .utils.logger import logger, ctx
  from .utils.source import ArrowSources
  from .utils.tmpdir import tmpdir
label_desc: Use image node_id 8 for calling a global function with example usage: _flatten_numpydoc_rules(rules) and returns: flattened