code: def _apply_section_children(self, section, hosts):
          
          for entry in section['entries']:
              for hostname in self._group_get_hostnames(entry['name']):
                  host = hosts[hostname]
                  for var_key, var_val in entry['hostvars'].items():
                      host['hostvars'][var_key] = var_val
docs: Add the variables for each entry in a 'children' section to the hosts
          belonging to that entry.