code: def _verify_python3_env():
      """Ensures that the environment is good for unicode on Python 3."""
      if PY2:
          return
      try:
          import locale
  
          fs_enc = codecs.lookup(locale.getpreferredencoding()).name
      except Exception:
          fs_enc = "ascii"
      if fs_enc != "ascii":
          return
  
      extra = ""
      if os.name == "posix":
          import subprocess
  
          try:
              rv = subprocess.Popen(
                  ["locale", "-a"],
                  stdout=subprocess.PIPE,
                  stderr=subprocess.PIPE,
              ).communicate()[0]
          except OSError:
              rv = b""
          good_locales = set()
          has_c_utf8 = False
  
          # Make sure we're operating on text here.
          if isinstance(rv, bytes):
              rv = rv.decode("ascii", "replace")
  
          for line in rv.splitlines():
              locale = line.strip()
              if locale.lower().endswith((".utf-8", ".utf8")):
                  good_locales.add(locale)
                  if locale.lower() in ("c.utf8", "c.utf-8"):
                      has_c_utf8 = True
  
          extra += "\n\n"
          if not good_locales:
              extra += (
                  "Additional information: on this system no suitable"
                  " UTF-8 locales were discovered. This most likely"
                  " requires resolving by reconfiguring the locale"
                  " system."
              )
          elif has_c_utf8:
              extra += (
                  "This system supports the C.UTF-8 locale which is"
                  " recommended. You might be able to resolve your issue"
                  " by exporting the following environment variables:\n\n"
                  "    export LC_ALL=C.UTF-8\n"
                  "    export LANG=C.UTF-8"
              )
          else:
              extra += (
                  "This system lists a couple of UTF-8 supporting locales"
                  " that you can pick from. The following suitable"
                  " locales were discovered: {}".format(
                      ", ".join(sorted(good_locales))
                  )
              )
  
          bad_locale = None
          for locale in os.environ.get("LC_ALL"), os.environ.get(
              "LANG"
          ):
              if locale and locale.lower().endswith(
                  (".utf-8", ".utf8")
              ):
                  bad_locale = locale
              if locale is not None:
                  break
          if bad_locale is not None:
              extra += (
                  "\n\nClick discovered that you exported a UTF-8 locale"
                  " but the locale system could not pick up from it"
                  " because it does not exist. The exported locale is"
                  " '{}' but it is not supported".format(bad_locale)
              )
  
      raise RuntimeError(
          "Click will abort further execution because Python 3 was"
          " configured to use ASCII as encoding for the environment."
          " Consult https://click.palletsprojects.com/python3/ for"
          " mitigation steps.{}".format(extra)
      )
  
imports: import codecs
  import os
  import sys
  from ._compat import PY2
label_desc: Use image node_id 3 for calling a global function with example usage: _verify_python3_env() without return types