Some errata and suggestion for chapter 2

[anotherlin]

• page 40, table 2.1, last line of table, for "round(x, [n])", "Rounds to the nearest multiple of 10-n" should rather be "Rounds to the nearest multiple of 10 power minus n". Or maybe "Rounds to the nearest multiple of 10 ** -n".
• page 43, line 7 (paragraph 2), last sentence "If a is a subsequence of b, then a < b." "subsequence" should rather be "prefix". If a = [ 2, 4, 6 ] and b = [ 1, 2, 3, 4, 5, 6, 7 ], then a is a subsequence of b, but a < b == False.
• page 44, second code snippet, "foo(4)" should rather be "f(4)" (the second code snippet is already mentioned in the errata).
• page 46, last code snippet, the comment for the tuple "# b = { 1, 2, 3, 10, 1, 2, 3 } ..." should be "# b = ( 1, 2, 3, 10, 1, 2, 3 ) ..." because it's a tuple and not a set.