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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 string_support(py3enc):
    '''Create byte-to-string and string-to-byte conversion functions for
    internal use.

    :param py3enc: Encoding used by Python 3 environment.
    :type py3enc: str
    '''
    if sys.version < '3':
        def bytes2str(b):
            '''Identity, returns the argument string (bytes).'''
            return b
        def str2bytes(s):
            '''Identity, returns the argument string (bytes).'''
            return s
    else:
        def bytes2str(b):
            '''Transforms bytes into string (Unicode).'''
            return b.decode(py3enc)
        def str2bytes(u):
            '''Transforms Unicode into string (bytes).'''
            return u.encode(py3enc)
    return (bytes2str, str2bytes)