hey are backed by a hash table
and also offer constant time lookup (and insertion for the mutable case).
Finally, the 'bytes' abstraction is any type that contains a sequence of bytes.
A 'bytes' value or byteseq associates integer keys (the indices) with integer
values between 0 and 255 (the byte values). In this way, they behave much like
arrays and tuples. However, one cannot put non-integer values into a byteseq.
</p>
<p>The table below summarizes the big-O complexity of various operations and other
info