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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 ext_language(ext, exts=None):
 """Language of the extension in those extensions If exts is supplied, then restrict recognition to those exts only If exts is not supplied, then use all known extensions True """

    languages = {
        '.py': 'python',
        '.py2': 'python2',
        '.py3': 'python3',
        '.sh': 'bash',
        '.bash': 'bash',
        '.pl': 'perl',
        '.js': 'javascript',
        '.txt': 'english',
    }
    ext_languages = {_: languages[_] for _ in exts} if exts else languages
    return ext_languages.get(ext)