Pickle in python3, error on concating string to bytes

Question

I am converting some code from python2 to 3 and saw an error that the 2to3 did not catch on a line:

pickle.dumps(('predskew', predskewData[0])) + pickleSep

That produces an error in python3:

pickledPredskewData = pickle.dumps(('predskew', predskewData[0])) + pickleSep

TypeError: can't concat str to bytes

I know from other posts on stack over flow I could perhaps use an encode? or a decode? I just wasn't sure where or what. So I did try this in python2:

pickleSep = ":::::"
pickle.dumps(('predskew',0)) + pickleSep

Which produces:

"(S'predskew'\np0\nI0\ntp1\n.:::::"

Also,

pickle.dumps(('predskew',0)) + pickleSep.encode()

Gives the same result.

Now if I try the same line in python3, I get what 'looks' like vastly different output:

pickle.dumps(('predskew', 0)) + pickleSep.encode()

Gives the output of:

b'\x80\x04\x95\x10\x00\x00\x00\x00\x00\x00\x00\x8c\x08predskew\x94K\x00\x86\x94.:::::'

So not sure my encode fix is the right approach as the answers seem different (unless it is the print just showing me the bytes itself?!)