def _parse_example(self, m, name, lineno):
<EOL>indent = len(m.group('<STR_LIT>'))<EOL>source_lines = m.group('<STR_LIT:source>').split('<STR_LIT:\n>')<EOL>self._check_prompt_blank(source_lines, indent, name, lineno)<EOL>self._check_prefix(source_lines[<NUM_LIT:1>:], '<STR_LIT:U+0020>'*indent + '<STR_LIT:.>', name, lineno)<EOL>source = '<STR_LIT:\n>'.join([sl[indent+<NUM_LIT:4>:] for sl in source_lines])<EOL>want = m.group('<STR_LIT>')<EOL>want_lines = want.split('<STR_LIT:\n>')<EOL>if len(want_lines) > <NUM_LIT:1> and re.match(r'<STR_LIT>', want_lines[-<NUM_LIT:1>]):<EOL><INDENT>del want_lines[-<NUM_LIT:1>]  <EOL><DEDENT>self._check_prefix(want_lines, '<STR_LIT:U+0020>'*indent, name,<EOL>lineno + len(source_lines))<EOL>want = '<STR_LIT:\n>'.join([wl[indent:] for wl in want_lines])<EOL>m = self._EXCEPTION_RE.match(want)<EOL>if m:<EOL><INDENT>exc_msg = m.group('<STR_LIT>')<EOL><DEDENT>else:<EOL><INDENT>exc_msg = None<EOL><DEDENT>options = self._find_options(source, name, lineno)<EOL>return source, options, want, exc_msg<EOL>
Given a regular expression match from `_EXAMPLE_RE` (`m`),
return a pair `(source, want)`, where `source` is the matched
example's source code (with prompts and indentation stripped);
and `want` is the example's expected output (with indentation
stripped).

`name` is the string's name, and `lineno` is the line number
where the example starts; both are used for error messages.