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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 _clean_isbn(isbn):
 """ Remove all non-digit and non "x" characters from given string. Args: isbn (str):
 isbn string, which will be cleaned. Returns: list: array of numbers (if "x" is found, it is converted to 10). """

    if isinstance(isbn, basestring):
        isbn = list(isbn.lower())

        # filter digits and "x"
        isbn = filter(lambda x: x.isdigit() or x == "x", isbn)

    # convert ISBN to numbers
    return map(lambda x: 10 if x == "x" else int(x), isbn)