def diffPrefsPrior(priorstring):
assert isinstance(priorstring, str)<EOL>prior = priorstring.split('<STR_LIT:U+002C>')<EOL>if len(prior) == <NUM_LIT:3> and prior[<NUM_LIT:0>] == '<STR_LIT>':<EOL><INDENT>[c1, c2] = [float(x) for x in prior[<NUM_LIT:1> : ]]<EOL>assert c1 > <NUM_LIT:0> and c2 > <NUM_LIT:0>, "<STR_LIT>"<EOL>return ('<STR_LIT>', c1, c2)<EOL><DEDENT>else:<EOL><INDENT>raise ValueError("<STR_LIT>".format(priorstring))<EOL><DEDENT>
Parses `priorstring` and returns `prior` tuple.