def unescape_single_character(match):
try:<EOL><INDENT>return DECODE_MAP[match.group(<NUM_LIT:0>)]<EOL><DEDENT>except KeyError:<EOL><INDENT>value = match.group(<NUM_LIT:0>)<EOL>if value == '<STR_LIT:\\>':<EOL><INDENT>raise ValueError("<STR_LIT>")<EOL><DEDENT>raise ValueError(<EOL>"<STR_LIT>".format(value))<EOL><DEDENT>
Unescape a single escape sequence found by regular expression.

:param match: Regular expression match object
:rtype: str
:raises: ValueError if the escape sequence is invalid