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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 convert_attribute_to_string(value):
 """ Convert an attribute value to a string. Converts the attribute value to a string if possible (get ``None`` if isn't a string type). .. versionadded:: 0.2 Parameters value : The Attribute value. Returns ------- s : str or None The ``str`` value of the attribute if the conversion is possible, or ``None`` if not. """

    if value is None:
        return value
    elif (sys.hexversion >= 0x03000000 and isinstance(value, str)) \
            or (sys.hexversion < 0x03000000 \
            and isinstance(value, unicode)):
        return value
    elif isinstance(value, bytes):
        return value.decode()
    elif isinstance(value, np.unicode_):
        return str(value)
    elif isinstance(value, np.bytes_):
        return value.decode()
    else:
        return None