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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 bool_env(key, default=False):
 """Parse an environment variable as a boolean switch `True` is returned if the variable value matches one of the following: - ``'1'`` - ``'y'`` - ``'yes'`` - ``'true'`` The match is case-insensitive (so ``'Yes'`` will match as `True`) Parameters key : `str` the name of the environment variable to find default : `bool` the default return value if the key is not found Returns ------- True if the environment variable matches as 'yes' or similar False otherwise Examples -------- True False False """

    try:
        return os.environ[key].lower() in TRUE
    except KeyError:
        return default