'Add re pattern
:param pattern:
:type pattern:
:param kwargs:
:type kwargs:
:return:
:rtype:'

def regex(self, *pattern, **kwargs):

    set_defaults(self._kwargs, kwargs)
    set_defaults(self._regex_defaults, kwargs)
    set_defaults(self._defaults, kwargs)
    pattern = self.rebulk.build_re(*pattern, **kwargs)
    part = ChainPart(self, pattern)
    self.parts.append(part)
    return part
