code: def header(self, title, level, key, width=80):
          
          linestyle_code = {1: "=", 2: "-", 3: "~"}
          if level not in linestyle_code:
              raise Exception("'level' argument has to be 1, 2 or 3")
          else:
              linestyle = linestyle_code[level]
  
          if key:
              return "\n".join([".. _%s" % key, "", title, linestyle * width])
          else:
              return "\n".join([title, "=" * width])
docs: Example::
  
              .. _header_2:
  
              Header 2
              -------------------------------------------------------------------
  
          **中文文档**