code: def flake8_wrapper():
      """Helper function to catch the worst style errors (e.g. unused variables)."""
      # http://pep8.readthedocs.io/en/latest/intro.html#error-codes
      cmd = [
          sys.executable,
          "-m",
          "flake8",
          "--select=F,E11",
          "imageio",
          "tests",
      ]
      ret_code = subprocess.call(cmd, cwd=ROOT_DIR)
      if ret_code == 0:
          print("No style errors found")
      else:
          sys.exit(ret_code)
  
file_path: imageio/tasks/test.py
imports: import os
  import sys
  import subprocess
  import webbrowser
  from invoke import task
  from ._config import ROOT_DIR
label_desc: Use image node_id 6 for calling a global function with example usage: flake8_wrapper() without return types