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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 all(self):
 r"""Returns all content in this node, regardless of whitespace or not. This includes all LaTeX needed to reconstruct the original source. ['\n', \newcommand{reverseconcat}[3]{#3#2#1}, '\n'] """

        for child in self.expr.all:
            if isinstance(child, TexExpr):
                node = TexNode(child)
                node.parent = self
                yield node
            else:
                yield child