code: def update(gandi, email, password, quota, fallback, alias_add, alias_del):
      
      options = {}
  
      if password:
          password = click.prompt('password', hide_input=True,
                                  confirmation_prompt=True)
          options['password'] = password
  
      if quota is not None:
          options['quota'] = quota
  
      if fallback is not None:
          options['fallback_email'] = fallback
  
      login, domain = email
  
      result = gandi.mail.update(domain, login, options, alias_add, alias_del)
  
      return result
docs: Update a mailbox.