s = "v=spf1 include:_cloud-netblocks1.googleusercontent.com include:_cloud-netblocks2.googleusercontent.com include:_cloud-netblocks3.googleusercontent.com include:_cloud-netblocks4.googleusercontent.com include:_cloud-netblocks5.googleusercontent.com ?all"
print([x.split(":")[1] for x in s.split() if ":" in x])
cyA9ICJ2PXNwZjEgaW5jbHVkZTpfY2xvdWQtbmV0YmxvY2tzMS5nb29nbGV1c2VyY29udGVudC5jb20gaW5jbHVkZTpfY2xvdWQtbmV0YmxvY2tzMi5nb29nbGV1c2VyY29udGVudC5jb20gaW5jbHVkZTpfY2xvdWQtbmV0YmxvY2tzMy5nb29nbGV1c2VyY29udGVudC5jb20gaW5jbHVkZTpfY2xvdWQtbmV0YmxvY2tzNC5nb29nbGV1c2VyY29udGVudC5jb20gaW5jbHVkZTpfY2xvdWQtbmV0YmxvY2tzNS5nb29nbGV1c2VyY29udGVudC5jb20gP2FsbCIKcHJpbnQoW3guc3BsaXQoIjoiKVsxXSBmb3IgeCBpbiBzLnNwbGl0KCkgaWYgIjoiIGluIHhdKQ==