Compatibility with Py27

[Former user]

There seems to be an issue in Py27 compatibility in v0.20.1.

In pybtex.richtext line 95, class BaseText(object, metaclass=ABCMeta) is not a Py27 compatible form.

[Andrey Golovizin]

Pybtex currently uses Python 2 syntax and 2to3 to convert the code to Python 3. The original pybtex/richtext.py file in the repository has

class BaseText(object):
    __metaclass__ = ABCMeta

so you must be looking at an already converted file.