code: def parse(self):
          
  
          self._config = _Config()
  
          self._setDefaults()
  
          for parser in self.parsers:
              for key, value in parser.parse(self, self._config).items():
                  key = self._sanitizeName(key)
                  if key not in self.configs:
                      raise UnknownConfigurationException(key)
                  if value is not None:
                      self._setConfig(key, value)
  
          self._ensureRequired()
          self._cast()
  
          return self._config
docs: Executes the registered parsers to parse input configurations.