code: def putheader(self, header, *values):
          
          if self.__state != _CS_REQ_STARTED:
              raise CannotSendHeader()
  
          if hasattr(header, 'encode'):
              header = header.encode('ascii')
          values = list(values)
          for i, one_value in enumerate(values):
              if hasattr(one_value, 'encode'):
                  values[i] = one_value.encode('latin-1')
              elif isinstance(one_value, int):
                  values[i] = str(one_value).encode('ascii')
          value = bytes(b'\r\n\t').join(values)
          header = header + bytes(b': ') + value
          self._output(header)
docs: Send a request header line to the server.
  
          For example: h.putheader('Accept', 'text/html')