code: def validate_config(self, project, config, actor=None):
          
          client = JiraClient(config['instance_url'], config['username'], config['password'])
          try:
              client.get_projects_list()
          except ApiError as e:
              self.raise_error(e)
  
          return config
docs: ```
          if config['foo'] and not config['bar']:
              raise PluginError('You cannot configure foo with bar')
          return config
          ```