code: func (r *Repository) Branch(name string) (*config.Branch, error) {
  	cfg, err := r.Storer.Config()
  	if err != nil {
  		return nil, err
  	}
  
  	b, ok := cfg.Branches[name]
  	if !ok {
  		return nil, ErrBranchNotFound
  	}
  
  	return b, nil
  }
docs: // Branch return a Branch if exists