The nacl library comes with sha256 and sha512 hashing libraries. They do not seem to offer any benefit over python's hashlib, but for completeness they are included. Creating a hash of a message is very simple:
import libnacl
msg = 'Is there someone else up there we could talk to?'
h_msg = libnacl.crypto_hash(msg)
crypto_hash defaults to sha256, sha512 is also available:
import libnacl
msg = 'Is there someone else up there we could talk to?'
h_msg = libnacl.crypto_hash_sha512(msg)