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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 parse_value_array(self, tup_tree):
 """ Parse a VALUE.ARRAY element and return the items in the array as a list of unicode strings, or None for NULL items. Whitespace is preserved. :: <!ELEMENT VALUE.ARRAY (VALUE | VALUE.NULL)*> """


        self.check_node(tup_tree, 'VALUE.ARRAY')

        children = self.list_of_various(tup_tree, ('VALUE', 'VALUE.NULL'))

        return children