code: def all(self):
          r
          for child in self.expr.all:
              if isinstance(child, TexExpr):
                  node = TexNode(child)
                  node.parent = self
                  yield node
              else:
                  yield child
docs: r"""Returns all content in this node, regardless of whitespace or
          not. This includes all LaTeX needed to reconstruct the original source.
  
          >>> from TexSoup import TexSoup
          >>> soup = TexSoup(r'''
          ... \newcommand{reverseconcat}[3]{#3#2#1}
          ... ''')
          >>> list(soup.all)
          ['\n', \newcommand{reverseconcat}[3]{#3#2#1}, '\n']