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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 str_to_boolean(input_str):
 """ a conversion function for boolean """

    if not isinstance(input_str, six.string_types):
        raise ValueError(input_str)
    input_str = str_quote_stripper(input_str)
    return input_str.lower() in ("true", "t", "1", "y", "yes")