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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 surround_parse(self, node, pre_char, post_char):
 """Parse the subnodes of a given node. Subnodes with tags in the `ignore` list are ignored. Prepend `pre_char` and append `post_char` to the output in self.pieces."""

        self.add_text(pre_char)
        self.subnode_parse(node)
        self.add_text(post_char)