code: def override(self, key, value):
          
          keys = key.split('.')
          if len(keys) > 1:
              if keys[0] != "plugins":
                  raise AttributeError("no such setting: %r" % key)
              self.plugins.override(keys[1:], value)
          else:
              self.overrides[key] = value
              self._uncache(key)
docs: Set a setting to the given value.
  
          Note that `key` can be in dotted form, eg
          'plugins.release_hook.emailer.sender'.