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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _find_lang(langdict, lang, script, region):
 """Return the entry in the dictionary for the given language information."""

    # Check if we should map this to a different locale.
    full_locale = _full_locale(lang, script, region)
    if (full_locale in _LOCALE_NORMALIZATION_MAP and
        _LOCALE_NORMALIZATION_MAP[full_locale] in langdict):
        return langdict[_LOCALE_NORMALIZATION_MAP[full_locale]]
    # First look for the full locale
    if full_locale in langdict:
        return langdict[full_locale]
    # Then look for lang, script as a combination
    if script is not None:
        lang_script = "%s_%s" % (lang, script)
        if lang_script in langdict:
            return langdict[lang_script]
    # Next look for lang, region as a combination
    if region is not None:
        lang_region = "%s_%s" % (lang, region)
        if lang_region in langdict:
            return langdict[lang_region]
    # Fall back to bare language code lookup
    if lang in langdict:
        return langdict[lang]
    # Possibly fall back to english
    if _may_fall_back_to_english(lang):
        return langdict.get("en", None)
    else:
        return None