code: def set_output_format( output_format ):
      
      if output_format == 'wiki':
          ttx = '== '
          xtt = ' =='
          tx = ''
          xt = ''
          capx = "'''"
          xcap = "'''"
          rx = '|'
          xr = '|'
          rspx = '|<|'
          xrsp = '>'
          cx = '|'
          xc = '|'
          hlx = '['
          hxl = ' '
          xhl = ']'
  
      elif output_format == "html":
          ttx = '<b>'
          xtt = '</b><hr>'
          tx = '<table border = "1">'
          xt = '</table><br><br>'
          capx = '<caption>'
          xcap = '</caption>'
          rx = '<tr>'
          xr = '</tr>'
          rspx = '<td rowspan='
          xrsp = '>'
          cx = '<td>'
          xc = '</td>'
          hlx = '<a href="'
          hxl = '">'
          xhl = "</a>"
  
      else:
          raise ValueError("unrecognized output_format %s" % output_format)
  
      return ttx, xtt, tx, xt, capx, xcap, rx, xr, cx, xc, rspx, xrsp, hlx, hxl, xhl
docs: Sets output format; returns standard bits of table. These are:
          ttx: how to start a title for a set of tables
          xtt: how to end a title for a set of tables
          tx: how to start a table
          xt: how to close a table
          capx: how to start a caption for the table
          xcap: how to close a caption for the table
          rx: how to start a row and the first cell in the row
          xr: how to close a row and the last cell in the row
          rspx: how to start a cell with a row span argument
          xrsp: how to close the row span argument
          cx: how to open a cell
          xc: how to close a cell