code: def _apply_overrides(settings, overrides, schema):
      
      if overrides:
          for k, v in six.iteritems(overrides):
              if k in schema:
                  if schema[k] is None:
                      settings[k] = v
                  elif type(schema[k]) is dict:
                      settings[k] = _apply_overrides(settings[k], overrides[k],
                                                     schema[k])
                  else:
                      raise Exception("Unexpected type found in schema '%s'" %
                                      type(schema[k]), level=ERROR)
              else:
                  log("Unknown override key '%s' - ignoring" % (k), level=INFO)
  
      return settings
docs: Get overrides config overlayed onto modules defaults.
  
      :param modules: require stack modules config.
      :returns: dictionary of modules config with user overrides applied.