code: def join(self, joiner, formatter=lambda s, t: t.format(s),
               template="{}"):
          
  
          return ww.s(joiner).join(self, formatter, template)
docs: Join values and convert to string
  
          Example:
  
              >>> from ww import l
              >>> lst = l('012')
              >>> lst.join(',')
              u'0,1,2'
              >>> lst.join(',', template="{}#")
              u'0#,1#,2#'
              >>> string = lst.join(',',\
                                    formatter = lambda x, y: str(int(x) ** 2))
              >>> string
              u'0,1,4'