invalid syntax after reformat

using yapf with pep8 style:

```
55 def is_header_present(name, definition, header_fields):
56 for idx in range(len(header_fields)):
57 field = definition[idx]
58 t, n = header_fields[idx]
59 if field[1] != n:
60 return False
61 if field[0] != t:
62 raise ParseError("Unexpected field type `%s' (should be `%s'), "
>> 63 "while parsing msg/def/field `%s/%s/%s'" % (
~ 64 field[0], t, name, definition, field))
65 return True
```

get reformatted as

```
55 def is_header_present(name, definition, header_fields):
56 for idx in range(len(header_fields)):
57 field = definition[idx]
58 t, n = header_fields[idx]
59 if field[1] != n:
60 return False
61 if field[0] != t:
62 raise ParseError("Unexpected field type `%s' (should be `%s'), "
>> 63 "while parsing msg/def/field `%s/%s/%s'" % (
~ 64 field[0], t, name, definition, field))
>> 65 return True
```

notice how "return True" statement got moved to invalid location...