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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def __auth_descriptor(self, api_info):
 """Builds an auth descriptor from API info. Args: api_info: An _ApiInfo object. Returns: A dictionary with 'allowCookieAuth' and/or 'blockedRegions' keys. """

    if api_info.auth is None:
      return None

    auth_descriptor = {}
    if api_info.auth.allow_cookie_auth is not None:
      auth_descriptor['allowCookieAuth'] = api_info.auth.allow_cookie_auth
    if api_info.auth.blocked_regions:
      auth_descriptor['blockedRegions'] = api_info.auth.blocked_regions

    return auth_descriptor