Construction. 

message = AnExampleMessage ()
message.CopyFrom (another_message)

Singular Fields. 

print (message.some_integer)
message.some_integer = 1234
if message.HasField ('optional_integer'):
    message.ClearField ('optional_integer')

Repeated Fields. 

size = len (messages.messages)
message = messages.messages [1234]
message = messages.messages.add ()

Byte Array Serialization. 

buffer = message.SerializeToString ()
message.ParseFromString (buffer)
message = AnExampleMessage.FromString (buffer)

Standard Stream Serialization. 

file.write (message.SerializeToString ())
message.ParseFromString (file.read ())
AnExampleMessage.FromString (file.read ())