code: def register_post(self, regex, callback):
          
          if callback is None:                                                                    # pragma: no cover
              if regex in self.post_registrations:
                  del self.post_registrations[regex]
          else:
              self.post_registrations[regex] = (re.compile(regex), callback)
docs: Register a regex for processing HTTP POST
          requests.  If the callback is None, any
          existing registration is removed.
  
          The callback will be called as:
  
              callback(path, postmap)