code: func isLeadingZeroPossible(countryCallingCode int) bool {
  	var mainMetadataForCallingCode *PhoneMetadata = getMetadataForRegionOrCallingCode(
  		countryCallingCode,
  		GetRegionCodeForCountryCode(countryCallingCode),
  	)
  	return mainMetadataForCallingCode.GetLeadingZeroPossible()
  }
docs: // Checks whether the country calling code is from a region whose national
  // significant number could contain a leading zero. An example of such a
  // region is Italy. Returns false if no metadata for the country is found.