code: def get_repo_config(self, repo='default'):
          
          for repo_config in self.repositories:
              if repo_config.name == repo or repo_config.url in RepositoryURL(repo):
                  return repo_config
  
          return None
docs: Retrieve configuration for a given repository.
  
          Args:
              repo (str): a repository "realm" (alias) or its URL
  
          Returns:
              RepositoryConfig: if there is configuration for that repository
              None: otherwise