new_contents: # class PrettyTable
  
  class PrettyTable(list):
      """ Overridden list class which takes a 2-dimensional list of 
          the form [[1,2,3],[4,5,6]], and renders HTML and LaTeX Table in 
          IPython Notebook. For LaTeX export two styles can be chosen."""
      def __init__(self, initlist=[], extra_header=None, print_latex_longtable=True):
          self.print_latex_longtable = print_latex_longtable
          if extra_header is not None:
              if len(initlist[0]) != len(extra_header):
                  raise ValueError("Header list must have same length as data has columns.")
              initlist = [extra_header]+list(initlist)
          super(PrettyTable, self).__init__(initlist)
      
      def latex_table_tabular(self):
          latex = ["\\begin{tabular}"]
          latex.append("{"+"|".join((["l"]*len(self[0])))+"}\n")
          for row in self:
              latex.append(" & ".join(map(format, row)))
              latex.append("\\\\ \n")
          latex.append("\\end{tabular}")
          return ''.join(latex)
      def latex_longtable(self):
          latex = ["\\begin{longtable}[c]{@{}"]
          latex.append("".join((["l"]*len(self[0]))))
          latex.append("@{}}\n")
          latex.append("\\toprule\\addlinespace\n")
          first = True
          for row in self:
              latex.append(" & ".join(map(format, row)))
              latex.append("\\\\\\addlinespace \n")
              if first:
                  latex.append("\\midrule\\endhead\n")
                  first = False
          latex.append("\\bottomrule \n \\end{longtable}")
          return ''.join(latex)
      
      def _repr_html_(self):
          html = ["<table>"]
          for row in self:
              html.append("<tr>")
              for col in row:
                  html.append("<td>{0}</td>".format(col))
              html.append("</tr>")
          html.append("</table>")
          return ''.join(html)
      def _repr_latex_(self):
          if self.print_latex_longtable: 
              return self.latex_longtable()
          else: 
              return self.latex_table_tabular()
  
subject: Add PrettyTable extension for Notebooks