unicode()
is a Python builtin, not part of BeautifulSoup. See the docs here.
unicode([object[, encoding[, errors]]])
If encoding and/or errors are given,
unicode() will decode the object which
can either be an 8-bit string or a
character buffer using the codec for
encoding. The encoding parameter is a
string giving the name of an encoding;
if the encoding is not known,
LookupError is raised. Error handling
is done according to errors; this
specifies the treatment of characters
which are invalid in the input
encoding. If errors is 'strict' (the
default), a ValueError is raised on
errors, while a value of 'ignore'
causes errors to be silently ignored,
and a value of 'replace' causes the
official Unicode replacement
character, U+FFFD, to be used to
replace input characters which cannot
be decoded. See also the codecs
module.
If you don't specify the encoding, sys.getdefaultencoding()
will be used by default.